HTTP download timeout - Stateful and stateless sessions

[Rayees]

Our file server is running inside the DMZ, and other boxes download files from DMZ

We have a weird issue, here are my steps 

1) Setup file server in DMZ, and run https server and keep the file iperf3-3.0.12-1.el6.x86_64.rpm under /var/www/html

2) Go to and node inside the cluster and try -> wget http://fileserver:8081/iperf3-3.0.12-1.el6.x86_64.rpm

3) Result : the file never get downloaded and get timeout error 

4) try ssh on fileserver from the node you tried to download and exit

5) Follow step 2 again, now file gets downloaded,  you can download the file for few minutes, after that you cannot 

What I noticed, whenever you establish a stateful session via ssh to file server, I am able to download, this session active few minutes, during that period it will work

Any idea how to fix this ? is it due to any filter ????