Cisco Security Appliance Command Line Configuration Guide, Version 7.0
Configuring WebVPN
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Configuring WebVPN

Table Of Contents

Configuring WebVPN

Observing WebVPN Security Precautions

Understanding Features Not Supported for WebVPN

Using SSL to Access the Central Site

Using HTTPS for WebVPN Sessions

Setting WebVPN HTTP/HTTPS Proxy

Configuring SSL/TLS Encryption Protocols

Authenticating with Digital Certificates

Enabling Cookies on Browsers for WebVPN

Understanding WebVPN Global and Group Policy Settings

Authenticating with Digital Certificates

Configuring DNS Globally

Configuring Global WebVPN Attributes

Creating and Applying WebVPN Policies

Creating Port Forwarding, URL, and Access Lists in Global Configuration Mode

Assigning Lists to Group Policies and Users in Group-Policy or User Mode

Enabling Features for Group Policies and Users

Assigning Users to Group Policies

Using a RADIUS Server

Using the Security Appliance Authentication Server

Configuring WebVPN Group Policy and User Attributes

Configuring Email

Configuring Email Proxies

Email Proxy Certificate Authentication

Configuring MAPI

Configuring Web Email: MS Outlook Web Access

Understanding WebVPN End User Set-up

Defining the End User Interface

Viewing the WebVPN Home Page

Viewing the WebVPN Application Access Panel

Viewing the Floating Toolbar

Requiring Usernames and Passwords

Communicating Security Tips

Configuring Remote Systems to Use WebVPN Features

Recovering from hosts File Errors in Application Access

Understanding the hosts File

Stopping Application Access Improperly

Reconfiguring hosts Files

Reconfiguring hosts File Automatically Using WebVPN

Reconfiguring hosts File Manually

Capturing WebVPN Data

WebVPN Capture Files

Activating the WebVPN Capture Tool

Locating and Uploading the WebVPN Capture Tool Output Files


Configuring WebVPN


This chapter describes WebVPN. WebVPN lets users establish a secure, remote-access VPN tunnel to a security appliance using a web browser. There is no need for either a software or hardware client. WebVPN provides easy access to a broad range of web resources and web-enabled applications from almost any computer on the Internet. These include secure access to the following resources:

Internal websites

Web-enabled applications

NT/Active Directory file shares

Email proxies, including POP3S, IMAP4S, and SMTPS

MS Outlook Web Access

MAPI

Port forwarding for access to other TCP-based applications.

WebVPN uses Secure Sockets Layer Protocol and its successor, Transport Layer Security to provide a secure connection between remote users and specific, supported internal resources that you configure at a central site. The security appliance recognizes connections that need to be proxied, and the HTTP server interacts with the authentication subsystem to authenticate users.

The network administrator provides access to WebVPN resources to users on a group basis. Users have no direct access to resources on the internal network.

This chapter includes the following sections:

Observing WebVPN Security Precautions

Understanding Features Not Supported for WebVPN

Using SSL to Access the Central Site

Authenticating with Digital Certificates

Enabling Cookies on Browsers for WebVPN

Understanding WebVPN Global and Group Policy Settings

Configuring Global WebVPN Attributes

Creating Port Forwarding, URL, and Access Lists in Global Configuration Mode

Enabling Features for Group Policies and Users

Configuring Email

Understanding WebVPN End User Set-up

Recovering from hosts File Errors in Application Access

Capturing WebVPN Data

Observing WebVPN Security Precautions

WebVPN connections on the security appliance are very different from remote access IPSec connections, particularly with respect to how they interact with SSL-enabled servers, and precautions to reduce security risks.

In a WebVPN connection, the security appliance acts as a proxy between the end user web browser and target web servers. When a WebVPN user connects to an SSL-enabled web server, the security appliance establishes a secure connection and validates the server SSL certificate. The end user browser never receives the presented certificate, so therefore cannot examine and validate the certificate.

The current implementation of WebVPN on the security appliance does not permit communication with sites that present expired certificates. Nor does the security appliance perform trusted CA certificate validation. Therefore, WebVPN users cannot analyze the certificate an SSL-enabled web-server presents before communicating with it.

To minimize the risks involved with SSL certificates:

1. Configure a group policy that consists of all users who need WebVPN access and enable the WebVPN feature only for that group policy.

2. Limit Internet access for WebVPN users. One way to do this is to disable URL entry. Then configure links to specific targets within the private network that you want WebVPN users to be able to access.

3. Educate users. If an SSL-enabled site is not inside the private network, users should not visit this site over a WebVPN connection. They should open a separate browser window to visit such sites, and use that browser to view the presented certificate.

Understanding Features Not Supported for WebVPN

The security appliance does not support the following features for WebVPN connections:

Active/Active or Active/Standby Stateful Failover, letting you configure two security appliances so that one takes over operation if the first one fails.

Inspection features under the Modular Policy Framework, inspecting configuration control.

Functionality the filter configuration commands provide, including the vpn-filter command.

NAT, reducing the need for globally unique IP addresses.

PAT, permitting multiple outbound sessions appear to originate from a single IP address.

QoS, rate limiting using the police command and priority-queue command.

Connection limits, checking either via the static or the Modular Policy Framework set connection command.

The established command, allowing return connections from a lower security host to a higher security host if there is already an established connection from the higher level host to the lower level host.

Using SSL to Access the Central Site

WebVPN uses SSL and its successor, TLS1 to provide a secure connection between remote users and specific, supported internal resources at a central site. This section includes the following topics:

Using HTTPS for WebVPN Sessions

Setting WebVPN HTTP/HTTPS Proxy

Configuring SSL/TLS Encryption Protocols

Using HTTPS for WebVPN Sessions

Establishing WebVPN sessions requires the following:

Using HTTPS to access the security appliance or load balancing cluster. In a web browser, users enter the security appliance IP address in the format https:// address where address is the IP address or DNS hostname of the security appliance interface.

Enabling WebVPN sessions on the security appliance interface that users connect to.

To permit WebVPN sessions on an interface, perform the following steps:


Step 1 In global configuration mode, enter the webvpn command to enter webvpn mode.

Step 2 Enter the enable command with the name of the interface that you want to use for WebVPN sessions.

For example, to enable WebVPN sessions on the interface called outside, enter the following:

hostname(config)# webvpn
hostname(config-webvpn)# enable outside


Note ASA supports either WebVPN or an ASDM administrative session on an interface, but not both simultaneously. To use ASDM and WebVPN at the same time, configure them on different interfaces.


Setting WebVPN HTTP/HTTPS Proxy

The security appliance can terminate HTTPS connections and forward HTTP/HTTPS requests to HTTP and HTTPS proxy servers. These servers act as intermediaries between users and the Internet. Requiring all Internet access via a server that the organization controls provides another opportunity for filtering to assure secure Internet access and administrative control.

To set values for HTTP and HTTPS proxy, enter the http-proxy and https-proxy commands in webvpn mode.

Configuring SSL/TLS Encryption Protocols

When you set SSL/TLS encryption protocols, be aware of the following:

Make sure that the security appliance and the browser you use allow the same SSL/TLS encryption protocols.

If you configure email proxy, do not set the security appliance SSL version to TLSv1 Only. MS Outlook and MS Outlook Express do not support TLS.

TCP Port Forwarding requires Sun Microsystems Java Runtime Environment (JRE) version 1.4.x and 1.5.x. Port forwarding does not work when a WebVPN user connects with some SSL versions, as follows:

Negotiate SSLv3

Java downloads

Negotiate SSLv3/TLSv1

Java downloads

Negotiate TLSv1

Java does NOT download

TLSv1Only

Java does NOT download

SSLv3Only

Java does NOT download


Authenticating with Digital Certificates

SSL uses digital certificates for authentication. The security appliance creates a self-signed SSL server certificate when it boots; or you can install in the security appliance an SSL certificate that has been issued in a PKI context. For HTTPS, this certificate must then be installed on the client. You need to install the certificate from a given security appliance only once.

Restrictions for authenticating users with digital certificates include the following:

Port forwarding does not work for WebVPN users who authenticate using digital certificates. JRE does not have the ability to access the web browser keystore. Therefore JAVA cannot use a certificate that the browser uses to authenticate a user, so it cannot start.

Email proxy supports certificate authentication with Netscape 7.x email clients only. Other email clients such as MS Outlook, MS Outlook Express, and Eudora lack the ability to access the certificate store.

Enabling Cookies on Browsers for WebVPN

Browser cookies are required for the proper operation of WebVPN. When cookies are disabled on the web browser, the links from the web portal home page open a new window prompting the user to log in once more.

Understanding WebVPN Global and Group Policy Settings

In general, the tunnel group and group policy commands for IPSec sessions do not apply for WebVPN. For WebVPN, use these same commands in global webvpn mode. The exceptions to this are:

WebVPN commands from the group policy WebVPN mode apply.

The banner, if any, that the client applies to WebVPN sessions.

The vpn-idletimeout, vpn-tunnel-protocol, and vpn-session-timeout commands apply.

Web VPN uses authentication, authorization, and accounting settings specific to WebVPN, which you configure with the global webvpn commands. Table 29-1 lists the commands specific to WebVPN for these features:

Table 29-1 Commands Specific to WebVPN

Command

accounting-server-group

authentication-server-group

authorization-server-group

authorization-dn-attributes

authoriziation-required



Note In Version 7.0.x, WebVPN does not support RADIUS with Expiry authentication.


Authenticating with Digital Certificates

WebVPN users that authenticate using digital certificates do not use global authentication and authorization settings. Instead, they use an authorization server to authenticate once the certificate validation occurs.

Configuring DNS Globally

WebVPN does not use the DNS settings of the group policy with which it has connected. WebVPN follows the security appliance global DNS settings. Ensure that the global DNS settings of the security appliance are configured properly.

Configuring Global WebVPN Attributes

Table 29-2 lists WebVPN attributes that apply globally to WebVPN users:

Table 29-2 Global WebVPN Attributes 

Function
Command
Default Value

Specifies the previously configured accounting servers to use with WebVPN.

accounting-server-group

None

Specifies the authentication method(s) for WebVPN users.

authentication

AAA

Specifies the previously configured authentication servers to use with WebVPN.

authentication-server-group

LOCAL

Specifies the previously configured authorization servers to use with WebVPN.

authorization-server-group

None

Requires users to authorize successfully to connect.

authorization-required

Disabled

Identifies the DN of the peer certificate to use as a username for authorization.

authorization-dn-attributes

Primary attribute: CN

Secondary attribute: OU

Specifies the name of the group policy to use.

default-group-policy

DfltGrpPolicy

Specifies the default idle timeout (in seconds).

default-idle-timeout

1800 seconds (30 minutes)

Enables WebVPN on the specified interface.

enable

Disabled

Identifies the proxy server for HTTP requests.

http-proxy

None

Identifies the proxy server for HTTPS requests.

https-proxy

None

Configures the HTML text that prompts a user to log in.

login-message

"Please enter your username and password."

Specifies the logo image that displays on the WebVPN login and home pages.

logo

Cisco logo

Configures the HTML text the security appliance presents to a user logging out.

logout-message

"Goodbye."

Identifies the NetBIOS Name Service server for CIFS name resolution.

nbns-server

None

Configures the prompt for a username at initial login to WebVPN.

username-prompt

"Login:"

Configures the prompt for the password at initial login to WebVPN.

password-prompt

"Password:"

Configures the HTML title string that is in the WebVPN browser title and on the title bar.

title

"WebVPN Service"

Configures the color of the title bars on the login, home and file access pages.

title-color

HTML #999CC, a lavender color

Configures the color of the text bars on the login, home, and file access pages.

text-color

White

Configures the color of the secondary title bars on the login, home and file access pages.

secondary-color

HTML #CCCCFF, a lavender color

Configures the color of the secondary text bars on the login, home and file access pages.

secondary-text-color

Black


You enter these WebVPN commands in webvpn mode. To enter webvpn mode, in global configuration mode, enter the webvpn command.

To reset all commands entered with the webvpn command to default values, use the no webvpn command.

Creating and Applying WebVPN Policies

Creating and applying WebVPN policies that govern access to resources at the central site includes the following tasks:

Creating Port Forwarding, URL, and Access Lists in Global Configuration Mode

Assigning Lists to Group Policies and Users in Group-Policy or User Mode

Enabling Features for Group Policies and Users

Assigning Users to Group Policies

Creating Port Forwarding, URL, and Access Lists in Global Configuration Mode

Use the port forward, url-list, and access-list commands in global configuration mode to configure the lists of ports to forward and URLs to present to WebVPN users, and their level of access.

Assigning Lists to Group Policies and Users in Group-Policy or User Mode

After you configure port forwarding and URL lists, use the port forward and url-list, and filter commands in webvpn group-policy or user mode to assign lists to group policies and/or users.

Enabling Features for Group Policies and Users

To enable features for group policies and users, issue the functions command in group-policy or user configuration mode.

Assigning Users to Group Policies

Assigning users to group policies simplifies configuration, by letting you apply policies to many users, rather than configuring policies for each user individually.There are two ways to assign users to group policies:

Using a RADIUS Server

Using a RADIUS server to authenticate users, assign users to group policies by following these steps:


Step 1 Authenticate the user with RADIUS and use the Class attribute to assign that user to a particular group policy.

Step 2 Set the class attribute to the group policy name in the format OU=group_name

For example, to set a WebVPN user to the SSL_VPN group, set the RADIUS Class Attribute to a value of OU=SSL_VPN; (Do not omit the semicolon.)


Using the Security Appliance Authentication Server

You can also configure users to authenticate to the security appliance internal authentication server, and assign these users to a group policy on the security appliance.

Configuring WebVPN Group Policy and User Attributes

Table 29-3 lists all WebVPN group policy and user attributes:

Table 29-3 WebVPN Group Policy Attributes

Function
Command
Default Value

Configures the name of the webtype access list.

filter

The security appliance does not enforce WebVPN access lists until you enter this command

Enables some or all of these WebVPN features: file access, file browsing, file entry, URL entry, port forwardng, MAPI proxy.

functions

Disabled

Sets the URL of the web page that displays upon login.

homepage

None

Configures the content and objects to filter from the HTML for this group policy.

html-content-filter

No filtering

Applies a list of WebVPN TCP ports to forward. The user interface displays the applications on this list.

port-forward

None

Configures the name of the port forwarding applet.

port-forward-name

"Application Access"

Applies a list of WebVPN servers and URLs that the user interface displays for end user access.

url-list

None


Configuring Email

WebVPN supports several ways to access email. This section includes the following methods:

Configuring Email Proxies

Configuring MAPI

Configuring Web Email: MS Outlook Web Access

Configuring Email Proxies

WebVPN supportsIMAP4S, POP3S, and SMTPS email proxies. Table 29-4 lists attributes that apply globally to Email proxy users:

Table 29-4 Global Email proxy Attributes

Function
Command
Default Value

Specifies the previously configured accounting servers to use with Email proxy.

accounting-server-group

None

Specifies the authentication method(s) for Email proxy users.

authentication

IMAP4S: Mailhost (required)

POP3S Mailhost (required)

SMTPS: AAA

Specifies the previously configured authentication servers to use with Email proxy.

authentication-server-group

LOCAL

Specifies the previously configured authorization servers to use with WebVPN.

authorization-server-group

None

Requires users to authorize successfully to connect.

authorization-required

Disabled

Identifies the DN of the peer certificate to use as a username for authorization.

authorization-dn-attributes

Primary attribute: CN

Secondary attribute: OU

Specifies the name of the group policy to use.

default-group-policy

DfltGrpPolicy

Enables Email proxy on the specified interface.

enable

Disabled

Defines the separator between the email and VPN usernames and passwords.

name-separator

":" (colon)

Configures the maximum number of outstanding non-authenticated sessions.

outstanding

20

Sets the port the email proxy listens to.

port

IMAP4S:993

POP3S: 995

SMTPS: 988

Specifies the default email server.

server

None.

Defines the separator between the email and server names.

server-separator

"@"



Note With the Eudora email client, SMTPS works only on port 465, even though the default port for SMTPS connections is 988.


Email Proxy Certificate Authentication

Certificate authentication for email proxy connections works with Netscape 7x email clients. Other email clients such as MS Outlook, MS Outlook Express, and Eudora lack the ability to access the certificate store.

Configuring MAPI

MAPI, also called MS Outlook Exchange proxy, has the following requirements:

MS Outlook Exchange must be installed on the remote computer.

You must enable MS Outlook Exchange Proxy on a security appliance interface. You do this by entering the functions command, which is a group-policy web vpn command. For example:

hostname(config)# group-policy group_policy_name attributes
hostname(config-group-policy)# webvpn
hostname(config-group-webvpn)# functions mapi
 
   

Provide the Exchange server NetBIOS name. The Exchange server must be on the same domain as the security appliance DNS server. For example:

hostname(config)# domain domain_name
hostname(config)#

Note An open MS Outlook client connected via MS Outlook Exchange Mail Proxy is always checking for mail on the Exchange Server, which keeps the connection open. As long as Outlook is open, the connection never times out, regardless of the settings.


Configuring Web Email: MS Outlook Web Access

Web email is MS Outlook Web Access for Exchange 2000, Exchange 5.5, and Exchange 2003. It requires an MS Outlook Exchange Server at the central site. It also requires that users perform the following tasks:

Enter the URL of the mail server in a browser in your WebVPN session.

When prompted, enter the email server username in the format domain\username.

Enter the email password.

Understanding WebVPN End User Set-up

This section is for the system administrator who sets up WebVPN for end users. It describes how to customize the end-user interface.

This section summarizes configuration requirements and tasks for a remote system. It specifies information to communicate to users to get them started using WebVPN. It includes the following topics:

Defining the End User Interface

Requiring Usernames and Passwords

Communicating Security Tips

Configuring Remote Systems to Use WebVPN Features

Defining the End User Interface

The WebVPN end user interface is a series of html panels. A user logs on to WebVPN by entering the IP address of a security appliance interface in the format https://address. The first panel that displays is the login screen.

Viewing the WebVPN Home Page

After the user logs in, the WebVPN home page displays (Figure 29-1).

Figure 29-1 WebVPN Home Page

The home page displays all of the WebVPN features you have configured, and its appearance reflects the logo, text, and colors you have selected. This sample home page includes all available WebVPN features with the exception of identifying specific file shares. It lets users browse the network, enter URLs, access specific websites, and use port forwarding to access TCP applications.

Viewing the WebVPN Application Access Panel

To start port forwarding, also called application access, a user clicks the "Start TCP application access" link. The Application Access Panel opens (Figure 29-2).

Figure 29-2 WebVPN Application Access Panel

This panel displays the TCP applications configured for this WebVPN connection. To use an application, with this panel open, the user starts the application in the normal way.

Viewing the Floating Toolbar

WebVPN also includes a floating toolbar (Figure 29-3).

Figure 29-3 WebVPN Floating Toolbar

Be aware of the following characteristics of the floating toolbar:

The toolbar lets you enter URLs, browse file locations, and choose preconfigured web connections without interfering with the main browser window.

If you configure your browser to block popups, the floating toolbar cannot display.

The floating toolbar represents the current WebVPN session. If you click the Close button, the security appliance prompts you to confirm that you want to end the WebVPN session.

See Table 29-6 for detailed information about using WebVPN.

Requiring Usernames and Passwords

Depending on your network, during a remote session users might have to log in to any or all of the following: the computer itself, an Internet servicde provider, WebVPN, mail or file servers, or corporate applications. Users might have to authenticate in many different contexts, requiring different information, such as a unique username, password, or pincode.

Table 29-5 lists the type of usernames and passwords that WebVPN users might need to know.

Table 29-5 Usernames and Passwords to Tell WebVPN Users 

Login Username/
Password Type
Purpose
Entered When

Computer

Access the computer

Starting the computer

Internet Service Provider

Access the Internet

Connecting to an Internet service provider

WebVPN

Access remote network

Starting WebVPN

File Server

Access remote file server

Using the WebVPN file browsing feature to access a remote file server

Corporate Application Login

Access firewall-protected internal server

Using the WebVPN web browsing feature to access an internal protected website

Mail Server

Access remote mail server via WebVPN

Sending or receiving email messages


Communicating Security Tips

Advise users always to log out from the WebVPN session. (To log out of WebVPN, click the logout icon on the WebVPN toolbar or close the browser.)

Advise users that using WebVPN does not ensure that communication with every site is secure. WebVPN ensures the security of data transmission between the remote PC or workstation and the security appliance on the corporate network. If the user then accesses a non-HTTPS web resource (located on the Internet or on the internal network), the communication from the corporate security appliance to the destination web server is not secure.

Configuring Remote Systems to Use WebVPN Features

Table 29-6 includes information about setting up remote systems to use WebVPN. It includes the following tasks:

Starting WebVPN

Using the WebVPN Floating Toolbar

Web Browsing

Network Browsing and File Management

Using Applications (Port Forwarding)

Using Email via Port Forwarding

Using Email via Web Access

Using Email via email proxy

Table 29-6 also provides information about the following:

WebVPN requirements, by feature

WebVPN supported applications

Client application installation and configuration requirements

Information you might need to provide end users

Tips and use suggestions for end users

It is possible you have configured user accounts differently and that different WebVPN features are available to each user. We have organized the information in Table 29-6 by feature, so you can skip over the information for unavailable features.

Table 29-6 WebVPN Remote System Configuration and End User Requirements 

Task
Remote System or End User Requirements
Specifications or Use Suggestions

Starting WebVPN

A connection to the Internet

Any Internet connection is supported, including:

Home DSL, cable, or dial-ups

Public kiosks

Hotel hook-ups

Airport wireless nodes

Internet cafes

A WebVPN-supported browser

We recommend the following browsers for WebVPN. Other browsers might not fully support WebVPN features.

On Microsoft Windows:

Internet Explorer version 6.0

Netscape version 7.2

Mozilla version 1.7 and above

Firefox 1.x

On Linux:

Mozilla version 1.7

Netscape version 7.2

Firefox 1.x

On Solaris:

Netscape version 7.2

On Macintosh OS X:

Safari version 1.0

Firefox 1.x

Cookies enabled on browser

Cookies must be enabled on the browser in order to access applications via port forwarding.

The URL for WebVPN

An https address in the following form:

https://address

where address is the IP address or DNS hostname of an interface of the security appliance (or load balancing cluster) on which WebVPN is enabled. For example: https://10.89.192.163 or https://cisco.example.com.

A WebVPN username and password

 

[Optional] A local printer

WebVPN does not support printing from a web browser to a network printer. Printing to a local printer is supported.

Using the WebVPN Floating Toolbar

 

A floating toolbar is available to simplify the use of WebVPN. The toolbar lets you enter URLs, browse file locations, and choose preconfigured web connections without interfering with the main browser window.

If you configure your browser to block popups, the floating toolbar cannot display.

The floating toolbar represents the current WebVPN session. If you click the Close button, the security appliance prompts you to confirm that you want to close the WebVPN session.


Tip TIP: To paste text into a text field, use Ctrl-V. Right-clicking is disabled on the WebVPN toolbar.


Web Browsing

Usernames and passwords for protected websites

Using WebVPN does not ensure that communication with every site is secure. See the Communicating Security Tips section.

 

The look and feel of web browsing with WebVPN might be different from what users are accustomed to. For example, when using WebVPN:

The WebVPN title bar appears above each web page

You access websites by:

Entering the URL in the Enter Web Address field on the WebVPN home page

Clicking on a preconfigured website link on the WebVPN home page

Clicking a link on a webpage accessed via one of the previous two methods

Also, depending on how you configured a particular account, it might be that:

Some websites are blocked

Only the websites that appear as links on the WebVPN home page are available

Network Browsing and File Management

File permissions configured for shared remote access

Only shared folders and files are accessible via WebVPN.

Server name and passwords for protected file servers

 

Domain, workgroup, and server names where folders and files reside

Users might not be familiar with how to locate their files through your organization network.

Patience

Do not interrupt the Copy File to Server command or navigate to a different screen while the copying is in progress. Interrupting the operation can cause an incomplete file to be saved on the server.

Using Applications

(called Port Forwarding or Application Access)

Note On Macintosh OS X, only the Safari browser supports this feature.

Note Because this feature requires installing Sun Microsystems Java™ Runtime Environment and configuring the local clients, and because doing so requires administrator permissions on the local system, it is unlikely that users will be able to use applications when they connect from public remote systems.


Caution Users should always close the Application Access window when they finish using applications by clicking the Close icon. Failure to quit the window properly can cause Application Access or the applications themselves to be disabled. See Recovering from hosts File Errors in Application Access for details.

Client applications installed

 

Cookies enabled on browser

 

Administrator privileges

User must be local administrator on the PC if you use DNS names to specify servers. This is because modifying the hosts file requires administrator privileges.

Sun Microsystems Java Runtime Environment (JRE) version 1.4.x and 1.5.x installed.

Javascript must be enabled on the browser. By default, it is enabled.

If JRE is not installed, a pop-up window displays, directing users to a site where it is available.

On rare occasions, the WebVPN port forwarding applet fails with JAVA exception errors. If this happens, do the following:

1. Clear the browser cache and close the browser.

2. Verify that no JAVA icons are in the computer task bar. Close all instances of JAVA.

3. Establish a WebVPN session and launch the port forwarding JAVA applet.

Client applications configured, if necessary.

Note The Microsoft Outlook client does not require this configuration step.

All non-Windows client applications require configuration.

To see if configuration is necessary for a Windows application, check the value of the Remote Server.

If the Remote Server contains the server hostname, you do not need to configure the client application.

If the Remote Server field contains an IP address, you must configure the client application.

To configure the client application, use the server's locally mapped IP address and port number. To find this information:

1. Start WebVPN on the remote system and click the Application Access link on the WebVPN home page. The Application Access window displays.

2. In the Name column, find the name of the server you want to use, then identify its corresponding client IP address and port number (in the Local column).

3. Use this IP address and port number to configure the client application. Configuration steps vary for each client application.

Note When you use an application over WebVPN, for example Outlook over Port Forwarding, if the application presents a URL, for example a URL within an email, clicking the URL does not open the site over WebVPN. You must cut and paste the URL into the Enter WebVPN (URL) Address box on the WebVPN home page to open the site in WebVPN.

Using Email
via Application Acces
s

Fulfill requirements for Application Access (See Using Applications)

To use mail, start Application Access from the WebVPN home page. The mail client is then available for use.

 

Note If you are using an IMAP client and you lose your mail server connection or are unable to make a new connection, close the IMAP application and restart WebVPN.

 

Other mail clients

We have tested Microsoft Outlook Express versions 5.5 and 6.0.

WebVPN should support other SMTPS, POP3S, or IMAP4S email programs via port forwarding, such as Netscape Mail, Lotus Notes, and Eudora, but we have not verified them.

Using Email via
Web Access

Web-based email product installed

Supported:

Outlook Web Access

For best results, use OWA on Internet Explorer 6.x or higher, Mozilla 1.7, or Firefox 1.x.

Louts iNotes

Other web-based email products should also work, but we have not verified them.

 

Using Email via
Email Proxy

SSL-enabled mail application installed

Do not set the security appliance SSL version to TLSv1 Only. Outlook and Outlook Express do not support TLS.

Supported mail applications:

Microsoft Outlook

Microsoft Outlook Express versions 5.5 and 6.0

Netscape Mail version 7

Eudora 4.2 for Windows 2000

Other SSL-enabled mail clients should also work, but we have not verified them.

 

Mail application configured

See instructions and examples for your mail application in the "Configuring Email" section.


Recovering from hosts File Errors in Application Access

It is very important to close the Application Access window properly. When you finish using Application Access, click the close icon. If you do not close the window properly:

The next time you try to start Application Access, it might be disabled; you receive a Backup HOSTS File Found error message.

The applications themselves might be disabled or might malfunction, even when you are running them locally.

These errors can result from terminating the Application Access window in any improper way. For example:

Your browser crashes while you are using Application Access.

A power outage or system shutdown occurs while you are using Application Access.

You minimize the Application Access window while you are working, then shut down your computer with the window active (but minimized).

This section includes the following topics:

Understanding the hosts File

Stopping Application Access Improperly

Reconfiguring hosts Files

Understanding the hosts File

The hosts file on your local system maps IP addresses to host names. When you start Application Access, WebVPN modifies the hosts file, adding WebVPN-specific entries. Stopping Application Access by properly closing the Application Access window returns the file to its original state.

Before invoking Application Access...

hosts file is in original state.

When Application Access starts....

WebVPN copies the hosts file to hosts.webvpn, thus creating a backup.

WebVPN then edits the hosts file, inserting WebVPN-specific information.

When Application Access stops...

WebVPN copies the backup file to the hosts file, thus restoring the hosts file to its original state.

WebVPN deletes hosts.webvpn.

After finishing Application Access...

hosts file is in original state.



Note Microsoft anti-spyware software blocks changes that the port forwarding JAVA applet makes to the hosts file. See www.microsoft.com for information on how to allow hosts file changes when using anti-spyware software.


Stopping Application Access Improperly

Once Application Access terminates abnormally, the hosts file is left in a WebVPN-customized state. WebVPN checks for this possibility the next time you start Application Access by searching for a hosts.webvpn file. If it finds one, you receive a Backup HOSTS File Found error message(see Figure 29-4), and Application Access is temporarily disabled.

Once you shut down Application Access improperly, you leave your remote access client/server applications in limbo. If you try to start these applications without using WebVPN, they might malfunction. You might find that hosts that you normally connect to are unavailable. This situation could commonly occur if you run applications remotely from home, fail to quit the Application Access window before shutting down the computer, then try to run the applications later from the office.

Reconfiguring hosts Files

To reenable Application Access or malfunctioning applications:

If you are able to connect to your remote access server, follow the steps in the section "Reconfiguring hosts File Automatically Using WebVPN."

If you are unable to connect to your remote access server from your current location or if you have made custom edits to the hosts file, follow the steps in the section "Reconfiguring hosts File Manually."

Reconfiguring hosts File Automatically Using WebVPN

If you are able to connect to your remote access server, follow these steps to reconfigure the hosts file and reenable both Application Access and the applications.


Step 1 Start WebVPN and log in. The home page opens.

Step 2 Click the Applications Access link. A Backup HOSTS File Found message displays. (See Figure 29-4.)

Figure 29-4 Backup HOSTS File Found Message

Step 3 Choose one of the following options:

Restore from backup = WebVPN forces a proper shutdown. WebVPN copies the hosts.webvpn backup file to the hosts file, restoring it to its original state, then deletes hosts.webvpn. You then have to restart Application Access.

Do nothing = Application Access does not start. You return to your remote access home page.

Delete backup = WebVPN deletes the hosts.webvpn file, leaving the hosts file in its WebVPN-customized state. The original hosts file settings are lost. Then Application Access starts, using the WebVPN-customized hosts file as the new original. Choose this option only if you are unconcerned about losing hosts file settings. If you or a program you use might have edited the hosts file after Application Access has shut down improperly, choose one of the other options, or edit the hosts file manually. (See the "Reconfiguring hosts File Manually" section.)


Reconfiguring hosts File Manually

If you are not able to connect to your remote access server from your current location, or if you have customized the hosts file and do not want to lose your edits, follow these steps to reconfigure the hosts file and reenable both Application Access and the applications.


Step 1 Locate and edit your hosts file.

Step 2 Check to see if any lines contain the string: # added by WebVpnPortForward
If any lines contain this string, your hosts file is WebVPN-customized. If your hosts file is WebVPN-customized, it looks similar to the following example:

123.0.0.3 server1 # added by WebVpnPortForward
123.0.0.3 server1.example.com vpn3000.com # added by WebVpnPortForward
123.0.0.4 server2 # added by WebVpnPortForward
123.0.0.4 server2.example.com.vpn3000.com # added by WebVpnPortForward
123.0.0.5 server3 # added by WebVpnPortForward
123.0.0.5 server3.example.com vpn3000.com # added by WebVpnPortForward
 
   
# Copyright (c) 1993-1999 Microsoft Corp.
#
# This is a sample HOSTS file used by Microsoft TCP/IP for Windows.
#
# This file contains the mappings of IP addresses to host names. Each
# entry should be kept on an individual line. The IP address should
# be placed in the first column followed by the corresponding host name.
# The IP address and the host name should be separated by at least one
# space.
#
# Additionally, comments (such as these) may be inserted on individual
# lines or following the machine name denoted by a '#' symbol.
#
# For example:
#
#      102.54.94.97     cisco.example.com          # source server
#       38.25.63.10     x.example.com              # x client host
 
   
123.0.0.1       localhost
 
   
 
   

Step 3 Delete the lines that contain the string: # added by WebVpnPortForward

Step 4 Save and close the file.

Step 5 Start WebVPN and log in. The home page appears.

Step 6 Click the Application Access link. The Application Access window appears. Application Access is now enabled.


Capturing WebVPN Data

WebVPN capture lets you log information about websites that do not display properly over a WebVPN connection. The data recorded can help your Cisco customer support engineer troubleshoot problems.


Note Enabling WebVPN capture affects the performance of the security appliance. Be sure to disable the capture after you generate the capture files that you need for troubleshooting.


WebVPN Capture Files

When you enable WebVPN capture using the capture command, the security appliance stores the data from the first URL visited in the following files:

capture name_ORIGINAL.000—Contains the data exchanged between the security appliance and the web server.

capture name_MANGLED.000—Contains the data exchanged between the security appliance and the browser.

For each subsequent capture, the security appliance generates additional pairs of matching capture name_ORIGINAL.<nnn> and capture name_MANGLED.<nnn> files and increments the file extensions. In the following example, the capture name sales was assigned to the capture, and the output of the dir command displays three sets of files from three URL captures:

hostname# dir
Directory of disk0:/
2952		-rw-		10931			10:38:32 Jan 19 2005 config
6		-rw-		5124096			19:43:32	 Jan 01 2003 cdisk.bin
3397		-rw-		5157			08:30:56 Feb 14 2005 sales_ORIGINAL.000
3398		-rw-		6396			08:30:56 Feb 14 2005 sales_MANGLED.000
3399		-rw-		4928			08:32:51 Feb 14 2005 sales_ORIGINAL.001
3400		-rw-		6167			08:32:51 Feb 14 2005 sales_MANGLED.001
3401		-rw-		5264			08:35:23 Feb 14 2005 sales_ORIGINAL.002
3402		-rw-		6503			08:35:23 Feb 14 2005 sales_MANGLED.002
hostname#

Activating the WebVPN Capture Tool


Note When you activate WebVPN capture, the icon appears in the WebVPN window.


To activate WebVPN capture, use the capture command from privileged EXEC mode.

capture capture-name type webvpn user webvpn-user [url url]

no capture capture-name

where:

capture-name is a name you assign to the capture, which is also prepended to the name of the capture files.

webvpn-user is the username to match for capture.

url is the URL prefix to match for data capture. Use one of the following two URL formats:

Use http://server/path to capture HTTP traffic to the server identified by server/path.

Use https://server/path to capture HTTPS traffic to the server identified by server/path.

If no URL is specified, all traffic is logged.

The following example creates a capture designated hr, which is configured to capture HTTP traffic for user2 visiting website wwwin.abcd.com/hr/people:

hostname# capture hr type webvpn user user2 url http://wwwin.abcd.com/hr/people
WebVPN capture started.
   capture name   hr
   user name      user2
   url            /http/0/wwwin.abcd.com/hr/people
hostname#

Locating and Uploading the WebVPN Capture Tool Output Files

To locate the WebVPN capture tool output files, use the dir command. The following example shows the output of the dir command including the ORIGINAL.000 and MANGLED.000 files that were generated:

hostname# dir
Directory of disk0:/
2952		-rw-		10931			10:38:32 Jan 19 2005 config
6		-rw-		5124096			19:43:32	 Jan 01 2003 cdisk.bin
3397		-rw-		5157			08:30:56 Feb 14 2005 hr_ORIGINAL.000
3398		-rw-		6396			08:30:56 Feb 14 2005 hr_MANGLED.000
hostname#
 
   

You can upload the WebVPN capture tool output files to another computer using the copy flash command. In the following example, the copy flash command is used to upload the hr_ORIGINAL.000 and hr_MANGLED.000 files via tftp:

hostname# copy flash:/hr_original.000 tftp://10.86.194.191/hr_original.000
Source filename [hr_original.000]?
Address or name of remote host [10.86.194.191]?
Destination filename [hr_original.000]?
!!!!!!
21601 bytes copied in 0.370 secs
 
   
hostname# copy flash:/hr_mangled.000 tftp://10.86.194.191/hr_mangled.000
Source filename [hr_mangled.000]?
Address or name of remote host [10.86.194.191]?
Destination filename [hr_mangled.000]?
!!!!!!
23526 bytes copied in 0.380 secs
 
   
hostname#

Note To conserve flash memory, delete the capture files from the security appliance when you no longer need them.