Cisco ASR 9000 Series Aggregation Services Router IP Addresses and Services Configuration Guide - Implementing Host Services and Applications on Cisco IOS XR Software for Cisco ASR 9000 Series Routers [Cisco ASR 9000 Series Aggregation Services Routers]

Table Of Contents

Implementing Host Services and Applications on Cisco ASR 9000 Series Routers

Contents

Prerequisites for Implementing Host Services and Applications on Cisco ASR 9000 Series Routers

Information About Implementing Host Services and Applications on Cisco ASR 9000 Series Routers

Network Connectivity Tools

Ping

Traceroute

Domain Services

TFTP Server

File Transfer Services

rcp

FTP

TFTP

Cisco inetd

Telnet

How to Implement Host Services and Applications on Cisco ASR 9000 Series Routers

Checking Network Connectivity

Checking Packet Routes

Configuring Domain Services

Prerequisites

Configuring a Router as a TFTP Server

Prerequisites

Configuring a Router to Use rcp Connections

Prerequisites

Troubleshooting Tips

Configuring a Router to Use FTP Connections

Troubleshooting Tips

Configuring a Router to Use TFTP Connections

Troubleshooting Tips

Configuring Telnet Services

Configuration Examples for Implementing Host Services and Applications on Cisco ASR 9000 Series Routers

Checking Network Connectivity: Example

Configuring Domain Services: Example

Configuring a Router to Use rcp, FTP, or TFTP Connections: Example

Additional References

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Implementing Host Services and Applications on Cisco ASR 9000 Series Routers

Host Services and Applications features on the Cisco ASR 9000 Series Aggregation Services Router are used primarily for checking network connectivity and the route a packet follows to reach a destination, mapping a hostname to an IP address or an IP address to a hostname, and transferring files between routers and UNIX workstations.

Note For a complete description of host services and applications commands listed in this module, refer to the Cisco ASR 9000 Series Aggregation Services Router IP Addresses and Services Command Reference publication. To locate documentation of other commands that appear in this module, use the command reference master index, or search online.

Feature History for Implementing Host Services and Applications on Cisco ASR 9000 Series Routers

Release

Modification

Release 3.7.2

This feature was introduced on Cisco ASR 9000 Series Routers.

Contents

•Prerequisites for Implementing Host Services and Applications on Cisco ASR 9000 Series Routers

•Information About Implementing Host Services and Applications on Cisco ASR 9000 Series Routers

•How to Implement Host Services and Applications on Cisco ASR 9000 Series Routers

•Configuration Examples for Implementing Host Services and Applications on Cisco ASR 9000 Series Routers

•Additional References

Prerequisites for Implementing Host Services and Applications on Cisco ASR 9000 Series Routers

The following prerequisites are required to implement host services and applications on Cisco ASR 9000 Series Routers:

•You must be in a user group associated with a task group that includes the proper task IDs. The command reference guides include the task IDs required for each command. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator.

•You must install and activate the Cisco IOS XR Unicast Routing Core Bundle for the Cisco IOS XR Host Services and Applications. The commands are installed as part of the Base Package, which is included in the Cisco IOS XR Unicast Routing Core Bundle.

For detailed information about bundle installation, see the Cisco ASR 9000 Series Aggregation Services Router Getting Started Guide.

•You must be familiar with Cisco IOS XR host services and applications commands. See the Cisco ASR 9000 Series Aggregation Services Router IP Addresses and Services Command Reference.

Information About Implementing Host Services and Applications on Cisco ASR 9000 Series Routers

To implement the host services and applications features discussed in this document, you should understand the following concepts:

•Network Connectivity Tools

•Domain Services

•TFTP Server

•File Transfer Services

•Cisco inetd

•Telnet

Network Connectivity Tools

Network connectivity tools enable you to check device connectivity by running traceroutes and pinging devices on the network.

Ping

The ping command is a common method for troubleshooting the accessibility of devices. It uses two Internet Control Message Protocol (ICMP) query messages, ICMP echo requests, and ICMP echo replies to determine whether a remote host is active. The ping command also measures the amount of time it takes to receive the echo reply.

The ping command first sends an echo request packet to an address, and then it waits for a reply. The ping is successful only if the echo request gets to the destination, and the destination is able to get an echo reply (hostname is alive) back to the source of the ping within a predefined time interval.

Traceroute

Where the ping command can be used to verify connectivity between devices, the traceroute command can be used to discover the paths packets take to a remote destination and where routing breaks down.

The traceroute command records the source of each ICMP "time-exceeded" message to provide a trace of the path that the packet took to reach the destination. You can use the IP traceroute command to identify the path that packets take through the network on a hop-by-hop basis. The command output displays all network layer (Layer 3) devices, such as routers, that the traffic passes through on the way to the destination.

The traceroute command uses the Time To Live (TTL) field in the IP header to cause routers and servers to generate specific return messages. The traceroute command sends a User Datagram Protocol (UDP) datagram to the destination host with the TTL field set to 1. If a router finds a TTL value of 1 or 0, it drops the datagram and sends back an ICMP time-exceeded message to the sender. The traceroute facility determines the address of the first hop by examining the source address field of the ICMP time-exceeded message.

To identify the next hop, the traceroute command sends a UDP packet with a TTL value of 2. The first router decrements the TTL field by 1 and sends the datagram to the next router. The second router sees a TTL value of 1, discards the datagram, and returns the time-exceeded message to the source. This process continues until the TTL increments to a value large enough for the datagram to reach the destination host (or until the maximum TTL is reached).

To determine when a datagram reaches its destination, the traceroute command sets the UDP destination port in the datagram to a very large value that the destination host is unlikely to be using. When a host receives a datagram with an unrecognized port number, it sends an ICMP port unreachable error to the source. This message indicates to the traceroute facility that it has reached the destination.

Domain Services

Cisco IOS XR domain services acts as a Berkeley Standard Distribution (BSD) domain resolver. The domain services maintains a local cache of hostname-to-address mappings for use by applications, such as Telnet, and commands, such as ping and traceroute. The local cache speeds the conversion of hostnames to addresses. Two types of entries exist in the local cache: static and dynamic. Entries configured using the domain ipv4 host or domain ipv6 host command are added as static entries, while entries received from the name server are added as dynamic entries.

The name server is used by the World Wide Web (WWW) for translating names of network nodes into addresses. The name server maintains a distributed database that maps hostnames to IP addresses through the DNS protocol from a DNS server. One or more name servers can be specified using the domain name-server command.

When an application needs the IP address of a host or the hostname of an IP address, a remote-procedure call (RPC) is made to the domain services. The domain service looks up the IP address or hostname in the cache, and if the entry is not found, the domain service sends a DNS query to the name server.

You can specify a default domain name that Cisco IOS XR software uses to complete domain name requests. You can also specify either a single domain or a list of domain names. Any IP hostname that does not contain a domain name has the domain name you specify appended to it before being added to the host table. To specify a domain name or names, use either the domain name or domain list command.

TFTP Server

It is too costly and inefficient to have a machine that acts only as a server on every network segment. However, when you do not have a server on every segment, your network operations can incur substantial time delays across network segments. You can configure a router to serve as a TFTP server to reduce costs and time delays in your network while allowing you to use your router for its regular functions.

Typically, a router that is configured as a TFTP server provides other routers with system image or router configuration files from its flash memory. You can also configure the router to respond to other types of services requests.

File Transfer Services

File Transfer Protocol (FTP), Trivial File Transfer Protocol (TFTP), and remote copy protocol (rcp) clients are implemented as file systems or resource managers. For example, pathnames beginning with tftp:// are handled by the TFTP resource manager.

The file system interface uses URLs to specify the location of a file. URLs commonly specify files or locations on the WWW. However, on Cisco routers, URLs also specify the location of files on the router or remote file servers.

When a router crashes, it can be useful to obtain a copy of the entire memory contents of the router (called a core dump) for your technical support representative to use to identify the cause of the crash. FTP, TFTP, or rcp can be used to save the core dump to a remote server. See the Cisco ASR 9000 Series Aggregation Services Router System Management Configuration Guide for information on executing a core dump.

rcp

Commands for rcp rely on the remote shell (rsh) server (or daemon) on the remote system. To copy files using rcp, you do not need to create a server for file distribution, as you do with TFTP. You need only to have access to a server that supports the rsh. Because you are copying a file from one place to another, you must have read permissions for the source file and write permission in the destination directory. If the destination file does not exist, rcp creates it for you.

Although Cisco rcp implementation emulates the functions of the UNIX rcp implementation—copying files among systems on the network—Cisco command syntax differs from the UNIX rcp command syntax. Cisco IOS XR software offers a set of copy commands that use rcp as the transport mechanism. These rcp copy commands are similar in style to the Cisco IOS XR TFTP copy commands, but they offer an alternative that provides faster performance and reliable delivery of data. These improvements are possible because the rcp transport mechanism is built on and uses the TCP/IP stack, which is connection-oriented. You can use rcp commands to copy system images and configuration files from the router to a network server and so forth.

FTP

FTP is part of the TCP/IP protocol stack, which is used for transferring files between network nodes. FTP is defined in RFC 959.

TFTP

TFTP is a simplified version of FTP that allows files to be transferred from one computer to another over a network, usually without the use of client authentication (for example, username and password).

Cisco inetd

Cisco Internet services process daemon (Cinetd) is a multithreaded server process that is started by the system manager after the system has booted. Cinetd listens for Internet services such as Telnet service, TFTP service, and so on. Whether Cinetd listens for a specific service depends on the router configuration. For example, when the tftp server command is entered, Cinetd starts listening for the TFTP service. When a request arrives, Cinetd runs the server program associated with the service.

Telnet

Enabling Telnet allows inbound Telnet connections into a networking device.

How to Implement Host Services and Applications on Cisco ASR 9000 Series Routers

This section contains the following procedures:

•Checking Network Connectivity (Optional)

•Checking Packet Routes (Optional)

•Configuring Domain Services (Optional)

•Configuring a Router as a TFTP Server (Optional)

•Configuring a Router to Use rcp Connections (Optional)

•Configuring a Router to Use FTP Connections (Optional)

•Configuring a Router to Use TFTP Connections (Optional)

•Configuring Telnet Services (Optional)

Checking Network Connectivity

As an aid to diagnosing basic network connectivity, many network protocols support an echo protocol. The protocol involves sending a special datagram to the destination host, then waiting for a reply datagram from that host. Results from this echo protocol can help in evaluating the path-to-host reliability, delays over the path, and whether the host can be reached or is functioning.

SUMMARY STEPS

1. ping [ipv4 | ipv6 | vrf vrf-name] [host-name | ip-address]

DETAILED STEPS

Command or Action

Purpose

Step 1

ping [ipv4 | ipv6 | vrf vrf-name] [host-name | ip-address]
Example:

RP/0/RSP0/CPU0:router# ping

Starts the ping tool that is used for testing connectivity.

Note If you do not enter a hostname or an IP address on the same line as the ping command, the system prompts you to specify the target IP address and several other command parameters. After specifying the target IP address, you can specify alternate values for the remaining parameters or accept the displayed default for each parameter.

Checking Packet Routes

The traceroute command allows you to trace the routes that packets actually take when traveling to their destinations.

SUMMARY STEPS

1. traceroute [ipv4 | ipv6 | vrf vrf-name] [host-name | ip-address]

DETAILED STEPS

Command or Action

Purpose

Step 1

traceroute [ipv4 | ipv6 | vrf vrf-name] [host-name | ip-address]
Example:

RP/0/RSP0/CPU0:router# traceroute

Traces packet routes through the network.

Note If you do not enter a hostname or an IP address on the same line as the traceroute command, the system prompts you to specify the target IP address and several other command parameters. After specifying the target IP address, you can specify alternate values for the remaining parameters or accept the displayed default for each parameter.

Configuring Domain Services

This task allows you to configure domain services.

Prerequisites

DNS-based hostname-to-address translation is enabled by default. If hostname-to-address translation has been disabled using the domain lookup disable command, reenable the translation using the no domain lookup disable command. See the Cisco ASR 9000 Series Aggregation Services Router IP Addresses and Services Command Reference for more information on the domain lookup disable command.

SUMMARY STEPS

1. configure

2. domain name domain-name

or

domain list domain-name

3. domain name-server server-address

4. domain {ipv4 | ipv6} host host-name {ipv4address | ipv6address}

5. end

or

commit

DETAILED STEPS
Command or Action

Purpose

Step 1

configure
Example:

RP/0/RSP0/CPU0:router# configure

Enters global configuration mode.

Step 2

domain name domain-name
or
domain list domain-name
Example:

RP/0/RSP0/CPU0:router(config)# domain name cisco.com
or
RP/0/RSP0/CPU0:router(config)# domain list domain1.com

Defines a default domain name used to complete unqualified hostnames.

Step 3

domain name-server server-address
Example:

RP/0/RSP0/CPU0:router(config)# domain name-server 192.168.1.111

Specifies the address of a name server to use for name and address resolution (hosts that supply name information).

Note You can enter up to six addresses, but only one for each command.

Step 4

domain {ipv4 | ipv6} host host-name {ipv4address | ipv6address}
Example:

RP/0/RSP0/CPU0:router(config)# domain ipv4 host1 192.168.7.18

(Optional) Defines a static hostname-to-address mapping in the host cache using IPv4 or IPv6.

Note You can bind up to eight additional associated addresses to a hostname.
Step 5

end
or
commit
Example:

RP/0/RSP0/CPU0:router(config)# end
or
RP/0/RSP0/CPU0:router(config)# commit
Saves configuration changes.

•When you issue the end command, the system prompts you to commit changes:
Uncommitted changes found, commit them before 
exiting(yes/no/cancel)? 
[cancel]:
–Entering yes saves configuration changes to the running configuration file, exits the configuration session, and returns the router to EXEC mode.

–Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes.

–Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes.

•Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session.
Configuring a Router as a TFTP Server

This task allows you to configure the router as a TFTP server so other devices acting as TFTP clients are able to read and write files from and to the router under a specific directory, such as slot0:, /tmp, and so on (TFTP home directory).

Note For security reasons, the TFTP server requires that a file must already exist for a write request to succeed.

Prerequisites

The server and client router must be able to reach each other before the TFTP function can be implemented. Verify this connection by testing the connection between the server and client router (in either direction) using the ping command.

SUMMARY STEPS

1. configure

2. tftp {ipv4 | ipv6} server {homedir tftp-home-directory} {max-servers number} [access-list name]

3. end

or

commit

4. show cinetd services

DETAILED STEPS
Command or Action

Purpose

Step 1

configure
Example:

RP/0/RSP0/CPU0:router# configure

Enters global configuration mode.

Step 2

tftp {ipv4 | ipv6} server {homedir tftp-home-directory} {max-servers number} [access-list name]
Example:

RP/0/RSP0/CPU0:router(config)# tftp ipv4 server access-list listA homedir disk0

Specifies:

•IPv4 or IPv6 address prefixes (required)

•Home directory (required)

•Maximum number of concurrent TFTP servers (required)

•Name of the associated access list (optional)
Step 3

end
or
commit
Example:

RP/0/RSP0/CPU0:router(config)# end
or
RP/0/RSP0/CPU0:router(config)# commit
Saves configuration changes.

•When you issue the end command, the system prompts you to commit changes:
Uncommitted changes found, commit them before 
exiting(yes/no/cancel)? 
[cancel]:
–Entering yes saves configuration changes to the running configuration file, exits the configuration session, and returns the router to EXEC mode.

–Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes.

–Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes.

•Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session.
Step 4

show cinetd services
Example:

RP/0/RSP0/CPU0:router# show cinetd services

Displays the network service for each process. The service column shows TFTP if the TFTP server is configured.
Configuring a Router to Use rcp Connections

This task allows you to configure a router to use rcp.

Prerequisites

For the rcp copy request to execute successfully, an account must be defined on the network server for the remote username.

If you are reading or writing to the server, the rcp server must be properly configured to accept the rcp read/write request from the user on the router. For UNIX systems, you must add an entry to the hosts file for the remote user on the rcp server.

SUMMARY STEPS

1. configure

2. rcp client username username

3. rcp client source-interface type instance

4. end

or

commit

DETAILED STEPS
Command or Action

Purpose

Step 1

configure
Example:

RP/0/RSP0/CPU0:router# configure

Enters global configuration mode.

Step 2

rcp client username username
Example:

RP/0/RSP0/CPU0:router(config)# rcp client username netadmin1

Specifies the name of the remote user on the rcp server. This name is used when a remote copy using rcp is requested. If the rcp server has a directory structure, all files and images to be copied are searched for or written relative to the directory in the remote user account.

Step 3

rcp client source-interface type instance
Example:

RP/0/RSP0/CPU0:router(config)# rcp client source-interface gigabitethernet 1/0/2/1

Sets the IP address of an interface as the source for all rcp connections.
Step 4

end
or

commit
Example:

RP/0/RSP0/CPU0:router(config)# end
or

RP/0/RSP0/CPU0:router(config)# commit
Saves configuration changes.

•When you issue the end command, the system prompts you to commit changes:
Uncommitted changes found, commit them before 
exiting(yes/no/cancel)? 
[cancel]:
–Entering yes saves configuration changes to the running configuration file, exits the configuration session, and returns the router to EXEC mode.

–Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes.

–Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes.

•Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session.
Troubleshooting Tips

When using rcp to copy any file from a source to a destination, use the following path format:
copy rcp://username@{hostname | ipaddress}/directory-path/pie-name target-device 
When using an IPv6 rcp server, use the following path format:
copy rcp://username@[ipv6-address]/directory-path/pie-name
See the copy command in the Cisco ASR 9000 Series Aggregation Services Router System Management Command Reference for detailed information on using rcp protocol with the copy command.

Configuring a Router to Use FTP Connections

This task allows you to configure the router to use FTP connections for transferring files between systems on the network. With the Cisco ASR 9000 Series Router implementation of FTP, you can set the following FTP characteristics:

•Passive-mode FTP

•Password

•IP address

SUMMARY STEPS

1. configure

2. ftp client passive

3. ftp client anonymous-password password

4. ftp client source-interface type instance

5. end

or

commit

DETAILED STEPS
Command or Action

Purpose

Step 1

configure
Example:

RP/0/RSP0/CPU0:router# configure

Enters global configuration mode.

Step 2

ftp client passive
Example:

RP/0/RSP0/CPU0:router(config)# ftp client passive

Allows the software to use only passive FTP connections.

Step 3

ftp client anonymous-password password
Example:

RP/0/RSP0/CPU0:router(config)# ftp client anonymous-password xxxx

Specifies the password for anonymous users.

Step 4

ftp client source-interface type instance
Example:

RP/0/RSP0/CPU0:router(config)# ftp client source-interface gigabitethernet 0/1/2/1

Specifies the source IP address for FTP connections.
Step 5

end
or

commit
Example:

RP/0/RSP0/CPU0:router(config)# end
or

RP/0/RSP0/CPU0:router(config)# commit
Saves configuration changes.

•When you issue the end command, the system prompts you to commit changes:
Uncommitted changes found, commit them before 
exiting(yes/no/cancel)? 
[cancel]:
–Entering yes saves configuration changes to the running configuration file, exits the configuration session, and returns the router to EXEC mode.

–Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes.

–Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes.

•Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session.
Troubleshooting Tips

When using FTP to copy any file from a source to a destination, use the following path format:
copy ftp://username:password@{hostname | ipaddress}/directory-path/pie-name target-device 
When using an IPv6 FTP server, use the following path format:
copy ftp://username:password@[ipv6-address]/directory-path/pie-name
If unsafe or reserved characters appear in the username, password, hostname, and so on, they have to be encoded (RFC 1738).

The following characters are unsafe:
"<", ">", "#", "%" "{", "}", "|", "ˆ", "~", "[", "]", and "`"
The following characters are reserved:
":", "/" "?", ":", "@", and "&"
The directory-path is a relative path to the home directory of the user. The slash (/) has to be encoded as %2f to specify the absolute path. For example:
ftp://user:password@hostname/%2fTFTPboot/directory/pie-name
See the copy command in the Cisco ASR 9000 Series Aggregation Services Router System Management Command Reference for detailed information on using FTP protocol with the copy command.

Configuring a Router to Use TFTP Connections

This task allows you to configure a router to use TFTP connections. You must specify the source IP address for a TFTP connection.

SUMMARY STEPS

1. configure

2. tftp client source-interface type instance

3. end

or

commit

DETAILED STEPS
Command or Action

Purpose

Step 1

configure
Example:

RP/0/RSP0/CPU0:router# configure

Enters global configuration mode.

Step 2

tftp client source-interface type instance
Example:

RP/0/RSP0/CPU0:router(config)# tftp client source-interface gigabitethernet 1/0/2/1

Specifies the source IP address for TFTP connections.
Step 3

end
or

commit
Example:

RP/0/RSP0/CPU0:router(config)# end
or

RP/0/RSP0/CPU0:router(config)# commit
Saves configuration changes.

•When you issue the end command, the system prompts you to commit changes:
Uncommitted changes found, commit them before 
exiting(yes/no/cancel)? 
[cancel]:
–Entering yes saves configuration changes to the running configuration file, exits the configuration session, and returns the router to EXEC mode.

–Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes.

–Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes.

•Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session.
Troubleshooting Tips

When using TFTP to copy any file from a source to a destination, use the following path format:
copy tftp://{hostname | ipaddress}/directory-path/pie-name target-device 
When using an IPv6 TFTP server, use the following path format:
copy tftp://[ipv6-address]/directory-path/pie-name
See the copy command in the Cisco ASR 9000 Series Aggregation Services Router System Management Command Reference for detailed information on using TFTP protocol with the copy command.

Configuring Telnet Services

This task allows you to configure Telnet services.

SUMMARY STEPS

1. configure

2. telnet [ipv4 | ipv6 | vrf vrf-name] server max-servers 1

3. end

or

commit

DETAILED STEPS
Command or Action

Purpose

Step 1

configure
Example:

RP/0/RSP0/CPU0:router# configure

Enters global configuration mode.

Step 2

telnet [ipv4 | ipv6 | vrf vrf-name] server max-servers 1
Example:

RP/0/RSP0/CPU0:router(config)# telnet ipv4 server max-servers 1

Enables one inbound Telnet server on the router.

Note This command affects only inbound Telnet connections to the router.
Step 3

end
or

commit
Example:

RP/0/RSP0/CPU0:router(config)# end
or

RP/0/RSP0/CPU0:router(config)# commit
Saves configuration changes.

•When you issue the end command, the system prompts you to commit changes:
Uncommitted changes found, commit them before 
exiting(yes/no/cancel)? 
[cancel]:
–Entering yes saves configuration changes to the running configuration file, exits the configuration session, and returns the router to EXEC mode.

–Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes.

–Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes.

•Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session.
Configuration Examples for Implementing Host Services and Applications on Cisco ASR 9000 Series Routers

This section provides the following configuration examples:

•Checking Network Connectivity: Example

•Configuring Domain Services: Example

•Configuring a Router to Use rcp, FTP, or TFTP Connections: Example

Checking Network Connectivity: Example

The following example shows an extended ping command sourced from the Router A Ethernet 0 interface and destined for the Router B Ethernet interface. If this ping succeeds, it is an indication that there is no routing problem. Router A knows how to get to the Ethernet of Router B, and Router B knows how to get to the Ethernet of Router A. Also, both hosts have their default gateways set correctly.

If the extended ping command from Router A fails, it means that there is a routing problem. There could be a routing problem on any of the three routers: Router A could be missing a route to the subnet of Router B's Ethernet, or to the subnet between Router C and Router B; Router B could be missing a route to the subnet of Router A's subnet, or to the subnet between Router C and Router A; and Router C could be missing a route to the subnet of Router A's or Router B's Ethernet segments. You should correct any routing problems, and then Host 1 should try to ping Host 2. If Host 1 still cannot ping Host 2, then both hosts' default gateways should be checked. The connectivity between the Ethernet of Router A and the Ethernet of Router B is checked with the extended ping command.

With a normal ping from Router A to Router B's Ethernet interface, the source address of the ping packet would be the address of the outgoing interface; that is, the address of the serial 0 interface (172.31.20.1). When Router B replies to the ping packet, it replies to the source address (that is, 172.31.20.1). This way, only the connectivity between the serial 0 interface of Router A (172.31.20.1) and the Ethernet interface of Router B (192.168.40.1) is tested.

To test the connectivity between Router A's Ethernet 0 (172.16.23.2) and Router B's Ethernet 0 (192.168.40.1), we use the extended ping command. With extended ping, we get the option to specify the source address of the ping packet.

In this example, the extended ping command verifies the IP connectivity between the two IP addresses 10.0.0.2 and 10.0.0.1.
ping
Protocol [ip]:
Target IP address: 10.0.0.1
Repeat count [5]:
Datagram size [100]:
Timeout in seconds [2]:
Extended commands? [no]: yes
Source address or interface: 10.0.0.2
Type of service [0]:
Set DF bit in IP header? [no]:
Validate reply data? [no]: yes
Data pattern [0xABCD]:
Loose, Strict, Record, Timestamp, Verbose[none]:
Sweep range of sizes? [no]:
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.25.58.21, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 2/11/49 ms
The traceroute command is used to discover the paths packets take to a remote destination and where routing breaks down. The traceroute command provides the path between the two IP addresses and does not indicate any problems along the path.
traceroute
Protocol [ip]:
Target IP address: ena-view3
Source address: 10.0.58.29
Numeric display? [no]:
Timeout in seconds [3]:
Probe count [3]:
Minimum Time to Live [1]:
Maximum Time to Live [30]:
Port Number [33434]:
Loose, Strict, Record, Timestamp, Verbose[none]:
Type escape sequence to abort.
Tracing the route to 171.71.164.199
1 sjc-jpollock-vpn.cisco.com (10.25.0.1) 30 msec 4 msec 4 msec
 2  15lab-vlan525-gw1.cisco.com (172.19.72.2) 7 msec  5 msec  5 msec
 3  sjc15-00lab-gw1.cisco.com (172.24.114.33) 5 msec  6 msec  6 msec
 4  sjc5-lab4-gw1.cisco.com (172.24.114.89) 5 msec  5 msec  5 msec
 5  sjc5-sbb4-gw1.cisco.com (171.71.241.162) 5 msec  6 msec  6 msec
 6  sjc5-dc5-gw1.cisco.com (171.71.241.10) 6 msec  6 msec  5 msec
 7  sjc5-dc1-gw1.cisco.com (171.71.243.2) 7 msec  8 msec  8 msec
 8 ena-view3.cisco.com (171.71.164.199) 6 msec * 8 msec
Configuring Domain Services: Example

The following example shows how to configure domain services on a router.

Defining the Domain Host
configure
domain ipv4 host host1 192.168.7.18
domain ipv4 host bost2 10.2.0.2 192.168.7.33
Defining the Domain Name
configure
domain name cisco.com
Specifying the Addresses of the Name Servers
configure
domain name-server 192.168.1.111
domain name-server 192.168.1.2
Configuring a Router to Use rcp, FTP, or TFTP Connections: Example

The following example shows how to configure the router to use rcp, FTP, or TFTP connections.

Using rcp
configure
rcp client username netadmin1
rcp client source-interface gigabitethernet 1/0/2/1
Using FTP
configure
ftp client passive
ftp client anonymous-password xxxx
ftp client source-interface gigabitethernet 0/1/2/1
Using TFTP
configure
tftp client source-interface gigabitethernet 1/0/2/1
Additional References

The following sections provide references related to implementing host services and addresses on Cisco ASR 9000 Series Routers.

Related Documents

Related Topic

Document Title

Cisco ASR 9000 Series Router host services and applications commands

Host Services and Applications Commands on Cisco ASR 9000 Series Routers module in the Cisco ASR 9000 Series Aggregation Services Router IP Addresses and Services Command Reference

Standards

Standards

Title

No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.

—

MIBs

MIBs

MIBs Link

—

To locate and download MIBs using Cisco IOS XR software, use the Cisco MIB Locator found at the following URL and choose a platform under the Cisco Access Products menu: http://cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml

RFCs

RFCs

Title

RFC-959

File Transfer Protocol

RFC-1738 and RFC-2732

Uniform Resource Locators (URL)

RFC-783

Trivial File Transfer Protocol

Technical Assistance

Description

Link

The Cisco Technical Support website contains thousands of pages of searchable technical content, including links to products, technologies, solutions, technical tips, and tools. Registered Cisco.com users can log in from this page to access even more content.

http://www.cisco.com/techsupport