FTP traffic denied with Strange behaviour

[Roby_Sreejith]

This is my rule:

The traffic is allowed, however suddenly the traffic will be denied and starts working after some time:

Please refer the logs:

The same traffic ( same porta and destination ) which was allowed suddenly denied in firewall.Data lane CPU percentage is below 20% during this time.

its 5050 firewall with 7.1.7 verson. Have any one faced this sitaution 

[reaper]

you can try setting up a packetcapture for your sessions on port 21 to verify if the data channel information is being negotiated properly and check if corresponding predict sessions are being created to allow these through

a flow basic / appid basic could also help figure out if the predict sessions are getting created (if the conrol channel is properly communicating the data channels)

[Roby_Sreejith · Accepted solution]

This seems to like an issue with control link times out before the data link connection happens.

There is a  timeout value for control connection which wait for data link connection. As there are no traffic reported during that time, while waiting for data link.