FTP load-balancing issue

Hello all,

 

 

We have a BigIP F5 LTM. Os version is BIG-IP 9.4.5

 

 

We used to have a virtual server setted up for all ports to load-balance 2 web and ftp servers.

 

During a DDOS, FTP got slower and slower (10 seconds delays before banner printing) but not HTTP.

 

As I thought FTP slowlyness were due to HTTP load, I then setted up 2 virtual server, one for TCP/80, other one for TCP/21 but nothing change.

 

 

Is there any way to optimize FTP virtual server ?

 

Should I create a FTP profile ? With which parameters ?

 

 

Sorry for these dummies questions, but I 'm quite new to F5 world.

 

 

Thanks,

 

JB