Maybe I need a simpler explanation: Computer A is main mail server Computer B is computer I want to forward from (to Computer A) - mainly system email Computer C is another computer on the LAN with computer A (behind the firewall) Computer D is totally unrelated to email scenario, just another node on the internet Test 1 - C and D can telnet to port 25 of A Test 2 - B cannot telnet to port 25 of A but can telnet to other open ports The B to A connection is what I want ... test 1 shows me that port 25 is open on A for both internal and external computers test 2 shows me that B can connect to A (so routing is working) but not on port 25 therefore no problem with my ISP letting port 25 traffic in so something must be set up along the route (through the internet) to block port 25 reuests from B (requests don't even show up at A when running tcpdump) Interesting enough, when I run tethereal on B and start a telnet to port 25, I immediately get what I think are reverse DNS requests from a bellnexxia machine. I think the Linksys router that is at the computer B site is blocking my nmap scans - I tried putting B in the routers DMZ but no luck Jay Crews (jpc@scooby.jaycrews.com) wrote*: > >Brian Johnson writes.... >> >> I can telnet to port 25 of the local machine from a different remote machine (my >> home machine through a different ISP) >> >> > >*snip snip* > >> >> Could the ISP be blocking port 25? Why would they do that? > >Absolutely! They could. >Because they don't want you running a mail server. >Usually the reason is because they don't want to risk you setting >up sendmail in such a way so that it will be an open relay, and >people use it (them - effectively the ISP) to send spam. >My ISP blocks port 80, because they don't want me running >a web server. (So, of course I just run it on port 8080. Dummies...) > >BUT, that being said, I thought you said you could connect from OUTSIDE >of you LAN. Didn't you say you could telnet port 25 from outside? On >a remote machine on another ISP? But could NOT connect from the LAN? > >> >> Can I forward the email over another port? How do you do that (a pointer to a >> howto url would be great)? > >Yes, and someone on this list, or the redhat-install list is doing >that, for that reason. Port 30 I think. >May want to ask there. > >But before you go to all that trouble, you should make sure port 25 >is being blocked. Try running nmap on it from outside and see what >ports are open. > > >> >> >> >> -- >> Psyche-list mailing list >> Psyche-list@redhat.com >> https://listman.redhat.com/mailman/listinfo/psyche-list >> > > >-- Jay Crews >jpc@jaycrews.com > > > > -- Psyche-list mailing list Psyche-list@redhat.com https://listman.redhat.com/mailman/listinfo/psyche-list
