Cisco IPS 4200 Series Sensors

Configuring IDS TCP Reset Using VMS IDS MC

Document ID: 47560

Updated: Oct 17, 2008



The document provides a sample configuration of the Cisco Intrusion Detection System (IDS) via the VPN/Security Management Solution (VMS), IDS Management Console (IDS MC). In this case, TCP Reset from the IDS Sensor to a Cisco router is configured.



Ensure that you meet these requirements before you attempt this configuration:

  • The Sensor is installed and configured for sensing necessary traffic.

  • The sniffing interface is spanned to the router outside interface.

Components Used

The information in this document is based on these software and hardware versions:

  • VMS 2.2 with IDS MC and Security Monitor 1.2.3

  • Cisco IDS Sensor 4.1.3S(63)

  • Cisco Router that runs Cisco IOS® Software Release 12.3.5

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.


Refer to Cisco Technical Tips Conventions for more information on document conventions.


In this section, you are presented with the information to configure the features described in this document.

Note: Use the Command Lookup Tool (registered customers only) to obtain more information on the commands used in this section.

Network Diagram

This document uses this network setup:



This document uses these configurations.

Router Light
Current configuration : 906 bytes
version 12.3
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
hostname light
enable password cisco
username cisco password 0 cisco
ip subnet-zero
ip ssh time-out 120
ip ssh authentication-retries 3
call rsvp-sync
fax interface-type modem
mta receive maximum-recipients 0
controller E1 2/0
interface FastEthernet0/0
 ip address
 duplex auto
 speed auto
interface FastEthernet0/1
 ip address
 duplex auto
 speed auto
interface BRI4/0
 no ip address
interface BRI4/1
 no ip address
interface BRI4/2
 no ip address
interface BRI4/3
 no ip address
ip classless
ip route
ip http server
ip pim bidir-enable
dial-peer cor custom
line con 0
line 97 108
line aux 0
line vty 0 4

Router House
Building configuration...

Current configuration : 797 bytes
version 12.3
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
hostname House
logging queue-limit 100
enable password cisco
ip subnet-zero
no ip domain lookup
interface Ethernet0
 ip address
 hold-queue 100 out
interface Ethernet1
 ip address
 ip classless
ip route
ip route
ip http server
no ip http secure-server
line con 0
 stopbits 1
line vty 0 4
 password cisco
scheduler max-task-time 5000

Initial Sensor Configuration

Note: If you have already performed the initial setup of your Sensor, proceed to the Import the Sensor into IDS MC section.

  1. Console into the Sensor.

    You are prompted for a username and password. If this is the first time you are consoling into the Sensor, you must login with the username cisco and password cisco.

  2. You are prompted to change the password and to re-type the new password to confirm.

  3. Type setup and enter the appropriate information at each prompt to set up basic parameters for your Sensor, as per this example:

        --- System Configuration Dialog --- 
    At any point you may enter a question mark '?' for help. 
    User ctrl-c to abort configuration dialog at any prompt. 
    Default settings are in square brackets '[]'. 
    Current Configuration: 
    hostname sensor5 
    telnetOption enabled 
    accessList ipAddress netmask 
    active-selection none 
    service webServer 
    ports 443 
    5 Save the config:   (It might take a few minutes for the sensor 
                          saving the configuration) 
    [0] Go to the command prompt without saving this config. 
    [1] Return back to the setup without saving this config. 
    [2] Save this configuration and exit setup. 
    Enter your selection[2]: 2 

Import the Sensor into IDS MC

Complete these steps in order to import the Sensor into the IDS MC.

  1. Browse to your Sensor. In this case, either or

  2. Login with the appropriate username and password.

    In this example, the username is admin and the password is cisco.

  3. Choose VPN/Security Management Solution > Management Center and click IDS Sensors.

  4. Click the Devices tab and choose Sensor Group.

  5. Highlight Global and click Create Subgroup.

  6. Enter the Group Name and ensure that Default is chosen, then click OK in order to add the subgroup into the IDS MC.


  7. Choose Devices > Sensor, highlight the subgroup created in the previous step (in this case, test), and click Add.

  8. Highlight the subgroup and click Next.


  9. Enter the details as per this example and click Next in order to continue.


  10. When you are presented with a message that states Successfully imported sensor configuration, click Finish in order to continue.


  11. Your Sensor is imported into the IDS MC. In this case, Sensor5 is imported.


Import the Sensor into Security Monitor

Complete these steps in order to import the Sensor into Security Monitor.

  1. At the VMS Server menu, choose VPN/Security Management Solution > Monitoring Center > Security Monitor.

  2. Select the Devices tab, then click Import and enter the IDS MC Server Information, as per this example.


  3. Select your Sensor (in this case, sensor5) and click Next in order to continue.


  4. If needed, update the NAT address for your Sensor, then click Finish in order to continue.


  5. Click OK in order to finish importing the Sensor from IDS MC into Security Monitor.


  6. You can now see that your Sensor is successfully imported


Use IDS MC for Signature Updates

This procedure explains how to use IDS MC for signature updates.

  1. Download the Network IDS Signature updates (registered customers only) and save them in the C:\PROGRA~1\CSCOpx\MDC\etc\ids\updates\ directory on your VMS Server.

  2. At the VMS server console, choose VPN/Security Management Solution > Management Center > IDS Sensors.

  3. Select the Configuration tab and click Updates.

  4. Click Update Network IDS Signatures.

  5. Select the signature you want to upgrade from the drop-down menu and click Apply in order to continue.


  6. Select the Sensor(s) to update and click Next in order to continue.


  7. After you are prompted to apply the update to the Management Center, as well as the Sensor, click Finish in order to continue.


  8. Telnet or console into the Sensor command line interface. You see information similar to this:

    Broadcast message from root (Mon Dec 15 11:42:05 2003): 
    Applying update IDS-sig-4.1-3-S63.  
    This may take several minutes. 
    Please do not reboot the sensor during this update. 
    Broadcast message from root (Mon Dec 15 11:42:34 2003): 
    Update complete. 
    sensorApp is restarting 
    This may take several minutes. 
  9. Wait for a few minutes to allow the upgrade to complete, then enter show version in order to verify.

    sensor5#show version 
    Application Partition: 
    Cisco Systems Intrusion Detection Sensor, Version 4.1(3)S63 
    Upgrade History: 
    * IDS-sig-4.1-3-S62           07:03:04 UTC Thu Dec 04 2003 
       IDS-sig-4.1-3-S63.rpm.pkg   11:42:01 UTC Mon Dec 15 2003 

Configure TCP Reset for IOS Router

Complete these steps in order to configure TCP reset for the IOS router.

  1. Choose VPN/Security Management Solution > Management Center > IDS Sensors.

  2. Select the Configuration tab, select your Sensor from Object Selector, then click Settings.

  3. Select Signatures, click Custom, and click Add in order to add a new signature.


  4. Enter the new Signature Name, then select the Engine (in this case, STRING.TCP).

  5. Check the appropriate radio button in order to customize the available parameters and then click Edit.

    In this example, the ServicePorts parameter is edited to change its value to 23 (for port 23). The RegexString parameter is also edited to add the value testattack. When this is complete, click OK to continue.


  6. Click the name of the signature in order to edit the Signature Severity and Actions or to Enable/Disable the signature.


  7. In this case, the severity is changed to High and the action Log & Reset is chosen. Click OK in order to continue.


  8. The complete signature looks similar to this:


  9. Choose Configuration > Pending, check the pending configuration to ensure it is correct, and click Save.


  10. Choose Deployment > Generate, and then click Apply in order to push the configuration changes to the Sensor.


  11. Choose Deployment > Deploy and click Submit.

  12. Check the checkbox next to your Sensor and click Deploy.

  13. Check the checkbox for the job in the queue and click Next in order to continue.


  14. Enter the Job Name and schedule the job as Immediate, then click Finish.


  15. Choose Deployment > Deploy > Pending.

    Wait a few minutes until all the pending jobs have been completed. The queue should then be empty.

  16. Choose Configuration > History in order to confirm the deployment.

    Ensure the status of the configuration is displayed as Deployed. This means that the Sensor configuration is updated successfully.



Use this section to confirm that your configuration works properly.

Launch the Attack and TCP Reset

Launch a test attack and check the results in order to verify that the Blocking process works correctly.

  1. Before the attack is launched, choose VPN/Security Management Solution > Monitoring Center > Security Monitor.

  2. Choose Monitor from the main menu and click Events.

  3. Click Launch Event Viewer.


  4. Telnet from one router to the other and type testattack in order to launch the attack.

    In this case, we Telnetted from the router Light to the router House. As soon as you press <space> or <enter>, after you type testattack, your Telnet session should be reset.

    Trying ... Open 
    User Access Verification 
    !--- The Telnet session is reset due to the 
    !--- signature "testattack" being triggered.
    [Connection to lost]
  5. From the Event Viewer, click Query Database for new events now.

    You see the alert for the previously launched attack


  6. In the Event Viewer, highlight the alarm, right-click it and select either View Context Buffer or View NSDB to view more detailed information about the alarm.



This section provides information you can use to troubleshoot your configuration.

Troubleshooting Procedure

Complete these steps in order to troubleshoot.

  1. In the IDS MC, choose Reports > Generate.

    Depending on the problem type, further details should be found in one of the seven available reports.


  2. While Blocking utilizes the Command and Control port to configure the router access-lists, TCP Resets are sent from the sniffing interface of the Sensor. Ensure you have spanned the correct port, using the set span command on the switch, similar to this:

    set span <src_mod/src_port><dest_mod/dest_port> both inpkts enable
    banana (enable) set span 2/12 3/6 both inpkts enable 
    Overwrote Port 3/6 to monitor transmit/receive traffic of Port 2/12 
    Incoming Packets enabled. Learning enabled. Multicast enabled. 
    banana (enable) 
    banana (enable) 
    banana (enable) show span 
    Destination     : Port 3/6              
    !--- Connect to sniffing interface of the Sensor.
    Admin Source    : Port 2/12        
    !--- In this case, connect to Ethernet1 of Router House. 
    Oper Source     : Port 2/12 
    Direction       : transmit/receive 
    Incoming Packets: enabled 
    Learning        : enabled 
    Multicast       : enabled 
  3. If TCP Reset is not working, login to the Sensor and enter the show event command.

    Launch the attack, and check to see whether or not the alarm is triggered. If the alarm is triggered, check to ensure it is set for the action type TCP reset.

Related Information

Updated: Oct 17, 2008
Document ID: 47560