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Stephane_87808's avatar
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Mar 30, 2012

SMTP optimization

Hello and please forgive me if I'm not in the right post group.



Our SMTP VS is just loadbalancing between two smtp server. I have tried a few parameters - like tcp-lan-optimized - but the time to get an answer from the smtp server through the Big IP LTM (through the VS_SMTP) is n times slower than the direct access to the server : would you have any idea of what could be implemented to have the same response time between the VS and the direct access to the server ?




Basic test, in dos command :



- telnet 25 takes 5 seconds to get the answer from the server



"220 ESMTP Service (Lotus Domino Release 8.5.2FP1) ready"




- telnet 25 gives immediately the prompt "220 smtp...."



Thanks for any advice.











2 Replies

  • Hi Stephane,



    Using a tcp-lan-optimized profile, what do you see in a tcpdump for the client and serverside connections? Where the 5 second delta?



    You can use a trace like this to see the client and serverside connections (replace and with your client and server addresses):



    tcpdump -ni 0.0 -Xs0 host or host



  • Hi Stephane,


    I will suggest you to not apply any optimization either LAN or wan just remove all the optimizations from ur VS and see how the connec tions and all go. then start adding the parameters to find out the exact cause of delay on ur SMTP server via LTM.