Connectrix - B Series Brocade: How to disable Telnet on a Brocade Fabric OS

Summary: How to disable Telnet on a Brocade FOS 6.x switch.

This article applies to This article does not apply to This article is not tied to any specific product. Not all product versions are identified in this article.

Symptoms

How to disable Telnet on a Brocade FOS 6.x switch.

Set ipfilter

Cause

Deny telnet

Resolution

 First, we must identify the rule number for Telnet.

Issue
ipfilter --show

Example below:
ipfilter --show  

Name: default_ipv4, Type: ipv4, State: defined
Rule  Source IP                    Protocol            Dest Port           Action
1     any                           tcp                    22              permit
2     any                           tcp                    23              permit <<<<<<<< Telnet Rule
3     any                           tcp                   897              permit
4     any                           tcp                   898              permit
5     any                           tcp                   111              permit
6     any                           tcp                    80              permit
7     any                           tcp                   443              permit
8     any                           udp                   161              permit
9     any                           udp                   111              permit
10    any                           udp                   123              permit
11    any                           tcp                   600 - 1023       permit
12    any                           udp                   600 - 1023       permit  

Name: default_ipv6, Type: ipv6, State: defined
Rule  Source IP                   Protocol             Dest Port           Action
1     any                          tcp                    22               permit
2     any                          tcp                    23               permit <<<<<Telnet Rule
3     any                          tcp                   897               permit
4     any                          tcp                   898               permit
5     any                          tcp                   111               permit
6     any                          tcp                    80               permit
7     any                          tcp                   443               permit
8     any                          udp                   161               permit
9     any                          udp                   111               permit
10    any                          udp                   123               permit
11    any                          tcp                   600 - 1023        permit
12    any                          udp                   600 - 1023        permit  

From this example, you can see that from the default policy the telnet rule is rule 2. Once the rule number for telnet has been identified follow the below procedure to disable Telnet. Assuming in the below output that the rule for telnet is 2, if the telnet rule is different as found in the above change the rule number in the below commands.

1.Copy default ipfilter policies       
Ipfilter --clone ipv4_no_telnet -from default_ipv4       
Ipfilter --clone ipv6_no_telnet -from default_ipv6
2.Delete current telnet policy for cloned policies       
Ipfilter --delrule ipv4_no_telnet -rule 2
Ipfilter --delrule ipv6_no_telnet -rule 2
3.Add new Telnet policy       
Ipfilter --addrule ipv4_no_telnet -rule 2 -sip any -dp 23 -proto tcp -act deny       
Ipfilter --addrule ipv6_no_telnet -rule 2 -sip any -dp 23 -proto tcp -act deny
4.Save policies       
Ipfilter --save
5.Activate new policies       
Ipfilter --activate ipv4_no_telnet       
Ipfilter --activate ipv6_no_telnet

Additional Information

Example of policies with telnet disabled.
 
Ipfilter --show  
Name: ipv4_no_telnet, Type: ipv4, State: active
Rule     Source IP                       Protocol            Dest Port                 Action
1          any                             tcp                   22                    permit
2          any                             tcp                   23                    deny
3          any                             tcp                   23                    permit
4          any                             tcp                   897                   permit
5          any                             tcp                   898                   permit
6          any                             tcp                   111                   permit
7          any                             tcp                   80                    permit
8          any                             tcp                   443                   permit
9          any                             udp                   161                   permit
10         any                             udp                   111                   permit
11         any                             udp                   123                   permit
12         any                             tcp                   600 - 1023            permit
13         any                             udp                   600 - 1023            permit  

Name: ipv6_no_telnet, Type: ipv6, State: active
Rule     Source IP                       Protocol            Dest Port                 Action
1          any                             tcp                   22                    permit
2          any                             tcp                   23                    deny
3          any                             tcp                   23                    permit
4          any                             tcp                   897                   permit
5          any                             tcp                   898                   permit
6          any                             tcp                   111                   permit
7          any                             tcp                   80                    permit
8          any                             tcp                   443                   permit
9          any                             udp                   161                   permit
10         any                             udp                   111                   permit
11         any                             udp                   123                   permit
12         any                             tcp                   600 - 1023            permit
13          any                            udp                   600 - 1023            permit

Affected Products

Connectrix B-Series Hardware

Products

Connectrix, Connectrix B-Series Hardware
Article Properties
Article Number: 000046018
Article Type: Solution
Last Modified: 09 Oct 2024
Version:  4
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