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madhava's avatar
madhava
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Jun 21, 2023
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Http server node receives partial http request big-ip load balancer

I am trying to setup BIG-IP load balancer first time, here is my setup. Client send traffic to virtual server and I have a node behind internal server. I am sending a simple get request to virtual s...
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  • Mohamed_Ahmed_Kansoh's avatar
    Mohamed_Ahmed_Kansoh
    Jun 22, 2023

    Hi madhava , 

    I see in the Pcap that no completed flow between client side and server side , Bigip Resets the connection when seeing the HTTP GET request , I see also this GET request maybe truncated , something corrupted in this Request and not follow the standard of http. 

    Please test the below steps : 
    1) change the standard http Virtual server to >>> Performance layer 4 , you have to remove http profile prior to changing the virtual server type. 
    Performance layer 4 Virtual server  means that >>> Bigip will forward all requests ( somehow acts as a router ) Not http Checks.

    2) repeat the Tcpdump command that I sent in the first reply , and upload it. 

    Let us see what will be the behavior and decide what is the suitable workaround for your issue. 

    Look forward to hearning from you soon 🙂 

Mohamed_Ahmed_Kansoh's avatar
Mohamed_Ahmed_Kansoh
Icon for MVP rankMVP

Hi madhava , 
First,  I'm reviewing with you your flow and Ips , So Am I correct in the below diagram according your configuration and design : 



Please confirm : Do you use SNAT Automap feature or not in Virtual server properities , you must configure it !

2nd ) 
I need you to execute only one TCPdump command to capture the Client and server sides traffic at the same time and to make it clear to follow the http and tcp stream well. 
use the below command : 

tcpdump -nni 0.0:nnnp -s0 -c 100000 -w /var/tmp/capture.pcap host 172.16.0.2

#where 172.16.0.2 is the IP of your machine or your client ip address.

using this command will capture all needed information in both sides ( Client & server side ) 
Please attach it in your reply to have a look on. 

Looking forward to hearning from you soon. 

madhava's avatar
madhava
Icon for Altocumulus rankAltocumulus
Jun 22, 2023

Hi Mohamed_Ahmed_Kansoh 

Thanks! My fix not working anymore, after changing "Standard" to "Performance(HTTP)" it worked for brief period then I am seeing same issue again. This time I tried with SNAT "Auto Map", but no luck still has same issue as described originally, yes diagram you described is correct and I am not using any specific profiles in VS configuration everything I left as default. Here I am attaching TCP dump as you suggested, appreciate your help.,

Thanks

Madhava

  • Mohamed_Ahmed_Kansoh's avatar
    Mohamed_Ahmed_Kansoh
    Icon for MVP rankMVP
    Jun 22, 2023

    Hi madhava , 

    I see in the Pcap that no completed flow between client side and server side , Bigip Resets the connection when seeing the HTTP GET request , I see also this GET request maybe truncated , something corrupted in this Request and not follow the standard of http. 

    Please test the below steps : 
    1) change the standard http Virtual server to >>> Performance layer 4 , you have to remove http profile prior to changing the virtual server type. 
    Performance layer 4 Virtual server  means that >>> Bigip will forward all requests ( somehow acts as a router ) Not http Checks.

    2) repeat the Tcpdump command that I sent in the first reply , and upload it. 

    Let us see what will be the behavior and decide what is the suitable workaround for your issue. 

    Look forward to hearning from you soon 🙂 

    • madhava's avatar
      madhava
      Icon for Altocumulus rankAltocumulus
      Jun 27, 2023

      Hi Mohamed_Ahmed_Kansoh,

      Thanks again for the response, out of frustration I just started everything a fresh from the scratch (creating new VS etc...). It magically started working, I don't remember doing anything diffrent but worked (though still not clear why it sends truncated http request), but your responses gave me a direction considering my limited experience with BIG-IP. In any case it is now working fine with basic setup, so not spending more time finding root cause until I get the issue again :). BTW mine is a testing environment, means my client and servers get deployed on the fly, so I added some delay to my client so servers get enough time to initialize before client start sending traffic  but not sure if that made any difference. Thanks again for the insight.

      Thanks  

      Madhava