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Re: Remove subnet from NAT pools without any impact

Hi zztop123 ,

Take a packet capture in the server side and see how this pool of NAT ips utilized. 

If you saw much traffic converted to source ips from the subnet that you want to remove it here you should be careful fron port exhaustion issue. 

If you don't much traffic use ips from the subnet you need to remove it you can delete it. 

Look at this article , it explains port exhaustion : https://my.f5.com/manage/s/article/K33355231

 

So the recommendation is to keep monitor in /var/log/ltm periodically to see if there is port exhaustion or not. 

If you found this log even one time , you should rollback and return the removed subnet again in the pool. 

 

6 Replies

  • zztop123's avatar
    zztop123
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    Thanks  Mohamed

    Can you please also see if you can find the procedure for removing the subnet from the Pool List and be able to add back.

    • Hi zztop123 , 

      Well , 
      Go to ( Local Traffic >> Address translation >> SNAT pool list >> open the SNAT list you need , then select all IPs that you need to remove  ) , you can record these ips in external txt files . 

      Click update and monitor the behavior , if there is an impact you can put these Ips from the txt file again and click update. 
      by this you did the rollback. 

      I want to ask you , maybe I miss understand you , you're speaking about SNAT pools which attached to virtual servers ? or you meant another pools 

      Please clarify 

      • zztop123's avatar
        zztop123
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        Hi Mohammed,

        Its not SNAT pool , just a NAT pool. is the procedure the same for it ? Please find the screen shot

         

  • zztop123's avatar
    zztop123
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    Hi Mohammad, We have a maintenanace window, and currentlyy seeing 2.4 mil onnections. The plan is move forward with one subnet deletion from the GUIand then monitor if the connections rebuild themselves?

    Does that sound an ok plan ?

    • Hi zztop123 , 

      Well sounds good. 

      Keep this subnet with you. 
      After deleting it : 

      monitor system performance and dropping rate. 
      Also look perodically in the log files for weired logs. 

      follow up with your subscribers if you found complains you should roll-back. 

      you can also filter in all connections that use this subnet in NATing like I recommended in the last replay.