I think my port 25 might be closed

How can I tell if port 25 on my machine is blocked? I can send e-mail from using Evolution and kmail without incident, but sylpheed-claws gives me an error connecting to the smtp server. I've verified that the smtp server info is correct. It does not require authorization. Using telnet to try to connect to the port yields: linux:/home/trey/sylpheed-claws # telnet localhost 25 Trying 127.0.0.1... telnet: connect to address 127.0.0.1: Connection refused Trying ::1... telnet: connect to address ::1: Connection refused I don't have a firewall enabled. Where in suse do I check this out? Thanks for any ideas.