I'm trying to connect to an sftp server from a CentOS 5.5 server. The connection is never established. When I run the command: nmap -p 22 -P0 <sftp server address>
PORT STATE SERVICE
22/tcp filtered ssh
I have similar development and staging servers on the same local network that are able to connect without any issues. There are no entries in iptables. Our firewall is setup to allow all outgoing requests. When I test the outgoing port 22 with: nmap -p 22 -P0 portquiz.net
22/tcp open ssh
it appears to be open. So the problem only seems to happen when it's this one live server, connecting to a specific sftp server. It's possible that the request is being blocked by a firewall on the end of the sftp server, but I don't understand why only this one server might be blocked. I was also able to connect to the sftp using a linode server that is outside our network.
This server was setup by somebody else. Are there any other settings on my end that could be causing this?