port 3391

This is really a question about how RDP Gateway works.   A web search suggests that UDP 3391 is an alternate, but not required, method for connecting to the RDP gateway, presumably to take advantage of the lower overhead associated with UDP.   This article seems to summarize the issue well.

http://windowsitpro.com/windows-server/change-remote-desktop-gateway-port

But this also means that your connectivity problem is somewhere else.

Thanks for the reply,

I did check our other RDgateway server, where we can open the published apps and still we see the drop line so  now we know that the drops are not the root issue.

what I dont unserstand is, normaly we see udp drops for 3391 why the log says ssl?

Thanks

Can you tel me what the SSL in the logs means? normaly we see TCp or UDP!

Back to how rdgateway works.  When tney connect to the published app, are they redirectex to a secondary connection on a nonstandard port?  I have seen this type of architecture with both Citrix and Vmware Horizon View.

Some organizations block nonstandard ports at their firewall, and you would not see any UTM log entry for a connect that never happened.

Thank you for the reply,

We did not cahnge any ports on the RDgateway and everything is defualt. you are right the application that they cannot open is located on the second RDS server.

Back to the oraginal question, as you can see in the firewall log it shows drop connection as SSL!! is this TCP or UDP?

Thanks

The answer is in the full Firewall log: proto="17" => UDP.  SSL can ride on UDP or TCP.  In order to speed up access, Google has Chrome use UDP 443 for SSL with its servers.

Cheers - Bob