Mar 27, 2026 - For details about updated CVE-2025-53521 (BIG-IP APM vulnerability), refer to K000156741.

Forum Discussion

Network_center1's avatar
Network_center1
Icon for Nimbostratus rankNimbostratus
Nov 04, 2019

Slow FTP connection behind F5

Hello there,   I have an issue I don't understand.   Some customers connect on one of our FTP server behind the F5. Public IP of the virtual server on port 21 > default pool > one server por...
application delivery
big-ip
Network_center1's avatar
Network_center1
Icon for Nimbostratus rankNimbostratus
Dec 08, 2019

Hello I found out the culprit in my problem....

 

There was an IP/account on internet spamming connection tries with a good ID but bad password, all the time, night and day....

It mays have overloaded the FTP server ( but only through the F5 strange ) and it slowed down any other connection from internet...

I deleted the account and banned the IP on the F5 > no more high latency....

 

I hate to spend weeks on stupid problems like that xD

 

  • PeteWhite's avatar
    PeteWhite
    Icon for Employee rankEmployee
    Dec 08, 2019
    How did they not notice that on the FTP server? As you say, frustrating but good that you have found it. Thanks for updating us.
    • Network_center1's avatar
      Network_center1
      Icon for Nimbostratus rankNimbostratus
      Dec 08, 2019

      Our windows team didn't notice anything, I requested a full access to investigate myself and find out there was a permanent connection with bad password....