I am now playing with DaemonPortOptions and Modifiers=b in sendmail to have computers use port 30 (but still want local connections through port 25 so trying two ports on local machine) Can now telnet on port 30 from computer B to computer A Still not getting mail through ... but at least now should be limited to sendmail options Brian Johnson (bjohnson@jecinc.on.ca) wrote*: > >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
