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Lutha_356435's avatar
Lutha_356435
Icon for Nimbostratus rankNimbostratus
Mar 28, 2018

Connection Resets from F5

Hi

 

Has anyone experienced a similar issue as i am having with my F5

 

I have VIP setuo to handle http connections for one of my sites. but users report getting a err conn rest message on chrome and firefox.

 

i have replucated the issue on my machine and it seems you have to hit the url on the server 4-5 times and it chucks a conn reset to the user.

 

i performed a wireshark capture and got the below

 

BIG-IP: [0x23f168a:700] Flow expired (sweeper) (idle timeout)

 

when i see the tcp rst cause. log i get the following

 

Mar 23 10:58:57 lb1a-cpt err tmm[17861]: 01230140:3: RST sent from 10.0.91.96:80 to 196.43.208.62:55300, [0x23c0eba:9280] {peer} TCP retransmit timeout

 

I dnt know where lese to have a look as i have looked at the tcp profile and disabled tcp rst cause.log

 

and i am sill receiving a conn reset and this happens in less than a minute

 

I appreciate all input to help diagnose this issue

 

application delivery
BIG-IP
LTM
  • HarshaPotharaju's avatar
    HarshaPotharaju
    Icon for Nimbostratus rankNimbostratus
    Mar 28, 2018

    Is there any firewall in between your F5 and backend server?

     

    In the wireshark, can you check 'Ethernet II' details?

     

    -Harsha.

     

  • Only1masterbla1's avatar
    Only1masterbla1
    Icon for Cirrus rankCirrus
    Mar 29, 2018

    F5 will not send any RST generally. Default TCP conn timeout is 5 mins. Collect network traces on client side & server side simultaneously and compare. Also check persistency and SNAT/Automap settings.

     

  • Lutha_356435's avatar
    Lutha_356435
    Icon for Nimbostratus rankNimbostratus
    Mar 29, 2018

    my f5 sits behind the firewall there is a switch connected to the F5 and I have checked routes between the two and they know how to forward traffic to each other to the backend.

     

    I have attached the Wireshark output between my VIP and external client.

     

    as you can see the resets are random as the Wireshark shows the other connections to the vip and out are fine but there's one in red which shows the problem area. where the vip sends a reset to the external client.

     

    this is all basic config i setup a few of these all the same and they work fine except of this particular one i have also attached a screenshot of my VIP config

     

     

    • Lutha_356435's avatar
      Lutha_356435
      Icon for Nimbostratus rankNimbostratus
      Apr 24, 2019

      Hi Hank

       

      Please try the following.

       

      1. Have you tried a packet capture, to show you where the reset is coming from?
      2. Also, check persistency and SNAT/Automap settings.
      3. create a new TCP profile and modify accordingly and apply to your vip.
      4. The Fast L4 profile had fixed this issue for me.
      5. Collect network traces on client side & server side simultaneously and compare.

      a packet capture will defs point you in the right direction as well as a dump of your

       

      If you willing you can skype me and i can try assist you with this.

       

    • Hank_Moody_3649's avatar
      Hank_Moody_3649
      Icon for Nimbostratus rankNimbostratus
      Apr 24, 2019

      Hi Lutha, thanks for your fast reply. I already had an support ticket for this case. We couldnt find a solution yet. I updated the severity at the highest now, because Exchange iApp is running so, sooo bad in our environment. I tried everything, googled everything. No solutions yet. There are alot of customers who are not able to work the last days. At first everything was running fine, but now we have such a poor perfomance, that 2010 clients can't even login OWA. Always "ERROR_CONNECTION_RESET".

       

      We checked everything, it is just the external services from exchange. If I access internal URL, everything is fast and stuff. I dont know what has happened.

       

      btw to your response:

       

      1. Yes. Clients take like 10 sec or more after hitting login to reach slow OWA or error blank page

         

      2. I checked, must be working.

         

      3. Dont know what exactly I have to change. Played with intervals, sizes, nagle, delayed acks.. no success.

         

      4. Could U explain me where I can find that Fast L4 profile?

       

      to 5. I did and already checked with support.

       

    • Lutha_356435's avatar
      Lutha_356435
      Icon for Nimbostratus rankNimbostratus
      Apr 25, 2019
      1. Could U explain me where I can find that Fast L4 profile?

      You can find it in TCP profiles