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Subrun's avatar
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Oct 07, 2019

F5 is not working as proxy solution - Need Help

In our scenario we are sending traffic to F5 from host on port 21 on F5 VIP F5 should forward that traffic to backend server on port 7021 but it's forwarding it on port 21. In pool, node and monitor i am using port 7021 but still it's forwarding traffic on port 21.


Virtual server is configured as standard server. Backend and monitor are configured as tcp 7021.


Below is the expected traffic flow which is not working>>>>>


Below is the tcpdump as the backend node is listening on port 7021 but as it's not getting traffic on port 7021 it's sending back Reset packet on VIP


just FYI is the self ip. If you see the packet from to it's sending with localport=21


Can you please help waht's wrong in my config and if you have query to understand the flow please let me know. Thank you in advance.

  • Make sure that Port Translation is enabled under VIP. config..

3 Replies

  • Sure, as soon as you post as sanitised virtual server configuration. Output the configuration using tmsh list ltm virtual <virtual name> , sanitise the output to remove customer identifiers and post a gist/hastebin/pastebin link to it here.

  • Subrun's avatar
    Icon for Cirrostratus rankCirrostratus

    Thanks for your help it was Port Translation not enabled...