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abhinay's avatar
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Jan 25, 2024

File transfer over 2GB fails over F5 LTM

Hi All,


Issue: File transfer over the VS fails when the size is beyond 2GB. For files less than 2GB the file is downloading but taking lot of time.


Profiles in place:

We are using default Cookie Persistence with HTTP Cookie Insert as Method but not defining any Cookie Name here. 

HTTP client/server Profile as Encrypted Cookie with a Passphrase

TCP client/server Profile as f5-tcp-progressive


From the Tcpdump weobserve that TCP Retransmission packets from Internal SelfIP to the backend Node. Appreciate if anybody can help here.

3 Replies

  • Hi abhinay,


    The issue may be caused by the type of virtual server, in a layer 7 virtual server the F5 reads all the packets because you have an HTTP profile to inject a cookie, so it takes a lot of time and is reset because the TCP profile of the Virtual server has some windows size and other checks controls to avoid an overflow of the VS.

     I recommend you use a Performance (Layer 4) virtual server an try the transmission of the packet again, if you need to insert the cookie I recommend you use a different VS for file transmission only.


    Hope it works.

  • Hi Sebastiansierra, 


    Thanks for the response. 


    I think once the TCP 3 way handshake is completed the same TCP session is used until the client closes the connection or until the idle timeout is expired i.e 300seconds in our case.


    So having HTTP profile which is injecting cookies for persistence should not be a factor to stop this file transfer. So the only thing I was trying to see is if TCP ZeroWindow is full but that is not the case too.


    So in general are you saying that on Layer 7 Virtual Server with HTTP profile with Cookie persistence we cannot transfer large files? and have to switch to Layer 4 Virtual Server?

  • clientIP -

    VIP -

    SelfIP -

    Node -


    I see RST from SelfIP to Node at 39.718 second. So it is not waiting for idle timeout of 5mins and then doing a RST. In 39th sec itself there is a RST from F5 to Node and then RST on client connection as well.