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Rusty_M_140798's avatar
Rusty_M_140798
Icon for Nimbostratus rankNimbostratus
Aug 15, 2014
Solved

SSL VPN Disconnect Issue

We currently have an issue with our SSL VPN connection disconnecting on random intervals. I do have a open support case and unfortunately not making any drastic headway, so reaching out here to see i...
application delivery
availability
deployment
performance
TMOS
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  • Matti_63169's avatar
    Matti_63169
    Jun 02, 2016

    Check the DNS settings of the F5 and make sure it can resolve the sslvpn fqdn.

     

    Background: We had similar issues, the PPP tunnel kept randomly closing and opening a new one, which caused the clients to reconnect, which in turn caused traffic not flowing while the PPP tunnel did a new handshake.

     

    There were no evidence in the LTM log why this happens, but the Edge client log revealed that DNS lookup for the APM endpoint (LTM VIP) didn't resolve. The client machine actually could resolve it, but the F5 itself couldn't. After changing the DNS servers in F5 to ones that resolved correctly the problem seems to have been solved.

     

Matti_63169's avatar
Matti_63169
Icon for Nimbostratus rankNimbostratus
Jun 02, 2016

Check the DNS settings of the F5 and make sure it can resolve the sslvpn fqdn.

 

Background: We had similar issues, the PPP tunnel kept randomly closing and opening a new one, which caused the clients to reconnect, which in turn caused traffic not flowing while the PPP tunnel did a new handshake.

 

There were no evidence in the LTM log why this happens, but the Edge client log revealed that DNS lookup for the APM endpoint (LTM VIP) didn't resolve. The client machine actually could resolve it, but the F5 itself couldn't. After changing the DNS servers in F5 to ones that resolved correctly the problem seems to have been solved.

 

  • Johnny__Xie_269's avatar
    Johnny__Xie_269
    Icon for Nimbostratus rankNimbostratus
    Jun 08, 2016
    Hello Matti, We had similar issue. May I know where you find the DNS lookup failure on BIG IP box? Where the DNS servers change you have done to resolve it? Thanks in advance!