Forum Discussion

DB's avatar
DB
Icon for Nimbostratus rankNimbostratus
May 29, 2009

X-Forwarded For equivelent for SMTP?

I'm running SMTP through LTM to Exchange 2008 servers, but due to my network architecture I have to autosnat the source IP to that of the F5. My Exchange servers therefore lose visibility of the origi...
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hooleylist's avatar
hooleylist
Icon for Cirrostratus rankCirrostratus
Jun 19, 2009
Citizen_elah was suggesting you could collect the TCP payload and then modify it to insert a custom header (like Comments or X-someheader-name) which contains the original client IP address. You'd need to be wary of collecting more than 4Mb of data though. And this would still require the mail server to actually do something with the custom header. It would probably be a lot easier to change the default gateway on the mail server to the BIG-IP...

 

 

SOL6578: TMM will crash if an iRule collects more than 4MB of data

 

https://support.f5.com/kb/en-us/solutions/public/6000/500/sol6578.html

 

 

If you're on 9.2.5+, you could potentially do this using a stream profile and STREAM::expression iRule (Click here).

 

 

SOL6741: Large payloads with use of the Stream profile cause the BIG-IP LTM system to crash (fixed in 9.2.5)

 

https://support.f5.com/kb/en-us/solutions/public/6000/700/sol6741.html

 

 

Aaron