Forum Discussion

Altocumulus

May 19, 2021

Routing problem for connect() in iRule

Good day.

I have an iRule script which must send email via connect command through corporate Exchange server:

set conn [connect -timeout 3000 -idle 30 -status conn_status -myaddr 127.1.1.254 $mailserv]

set data "HELO\r\nMAIL FROM: $mailfrom\r\nRCPT TO: $email\r\nDATA\r\nSUBJECT: S3 rate limit exceeded 3000 bytes/s\r\nMIME-Version: 1.0;\r\nContent-Type: text/html;charset=iso-8859-1;\r\n\r\n\r\nRate limit exceeded for $mycookie\r\n\r\n.\r\nQUIT\r\n"

set send_info [send -timeout 3000 -status send_status $conn $data]

I can connect to 25 port of Exhange server in corresponding partition:

 # telnet x.y.z.25 25 -b 127.1.1.254
Trying x.y.z.25...
Connected to x.y.z.25.
Escape character is '^]'.
220 ZZZZ Microsoft ESMTP MAIL Service ready at Wed, 19 May 2021 16:10:42 +0300
^C^]

But in LTM log I got the errors:

 <CLIENT_CLOSED> - Connection failed for x.y.z.25:25 [Routing problem] (line 2)     invoked from within "connect -timeout 3000 -idle 30 -status conn_status -myaddr 127.1.1.254"

What should I do to fix the problem?

Thank you.

application delivery

iRules

LTM

AlexBCT
May 19, 2021
Hi Vladimir,

Have you checked if the TMOS interfaces have access to the mailserver IP using TMOS routes? (Under "Network - Routes" in the GUI)
As the "telnet" command is run from the management side, it may use either the management interface or a TMOS interface for outbound traffic, whereas the iRules will only use TMOS interfaces for communication.

Here is more details on the (sometimes tricky) management routing; https://support.f5.com/csp/article/K13284

Hope this helps.

AlexBCT
Cumulonimbus
May 19, 2021
Hi Vladimir,

Have you checked if the TMOS interfaces have access to the mailserver IP using TMOS routes? (Under "Network - Routes" in the GUI)
As the "telnet" command is run from the management side, it may use either the management interface or a TMOS interface for outbound traffic, whereas the iRules will only use TMOS interfaces for communication.

Here is more details on the (sometimes tricky) management routing; https://support.f5.com/csp/article/K13284

Hope this helps.
- Vladimir_Shishk
  Altocumulus
  May 20, 2021
  Hi, Alex, thank you for your answer.
  I added a static route to mailserver through Common partition and mailserver stopped to become unreachable, thank you.
  - AlexBCT
    Cumulonimbus
    May 20, 2021
    Hi Vladimir,
    
    Glad to hear it got solved and nice job on the syntax troubleshooting ;)
    Would be great if you can flag the question as Answered so it may be closed and help the rest of the community.