Hello,
recently my backup jobs on a server behind a firewall started to fail.
I have set Remote Agent to use TCP ports 10001-10025 and on the firewall I have opened ports 10000(!) to 10025 for outgoing traffic to the remote server to be backed up. In addition ports 6101-6106 are opened for incoming traffic from the remote server to the local media server. This worked for many months without problems.
According to the firewall logs, the local server first started communication to port 10000 on the remote server. Then the local server continues to communicate to port 10001 (with a source port 'X') on the remote server. So far so good. But after the first few KB were transferred to backup, the remote server suddenly starts a communication on its own from source port 10001 to destination port 'X' on the local server. 'X' is alway a different port above 1025. This connection is, of course, blocked by the firewall, since incoming connections other than to ports 6101-6106 are not allowed.
What ist going on there? Why is the remote server starting a communication at all? It almost looks, as if the Remote Agent started a new communication instead of answering to the communication initiated by the local server.
Both servers are Windows Server 2003.
Any ideas?
Wolfgang
