Forum Discussion

cjunior_138458's avatar
cjunior_138458
Icon for Altostratus rankAltostratus
Aug 11, 2015

Why the BigIP does not forwarding my telnet on port 25?

Hi,

 

Why the BigIP does not forwarding my telnet on port 25?

 

  1. If I do telnet to the VS:25, apparently connects to the VS but not forwarding to the server:25. An irule is not able to log events here too.

     

  2. If I do telnet directly to the server:25, everything works fine.

     

  3. If I change the VS port and do telnet to the VS:2525, e.g., is forwarding to the server:25 and works fine.

     

  4. And, if I connect in VS:25 with another tool (e.g. http://www.adminkit.net/telnet.aspx),,) everything works fine.

     

So, it looks like the problem is the telnet command to the VS:25.

 

Think I probably forgot some trick in this scenario.

 

Any help, I appreciate.

 

My BIG-IP: v. 11.5.1

 

Regards.

 

application delivery
LTM

2 Replies

Sort By
  • Patrik_Jonsson's avatar
    Patrik_Jonsson
    Icon for MVP rankMVP
    Aug 12, 2015

    I don't think the LTM establishes the serverside connection on a normal VS until there is data. Have you tried sending commands over the session?

     

    I know this does not match all the statements above, but give it a shot?

     

    Have you tried tcpdump?

     

    Can you post the virtual server configuration for the virtual servers you mentioned?

     

    /Patrik

     

  • Patrik_Jonsson's avatar
    Patrik_Jonsson
    Icon for MVP rankMVP
    Aug 14, 2015

    If you use telnet and the data does not reach the vs free you initiate the connection that could be it. Have you tried catching traffic on your fw with tcp dump to see if it could be some ips blocking you?