Port 25 blocked; can't send mail

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Level 1

40 points

Port 25 blocked; can't send mail

I didn't keep track when the problem started a couple of weeks ago, as I thought it was with my ISP: about mid-afternoon I would stop being able to send outgoing mail, although incoming mail would still get through and I had no trouble browsing the web. In the early evening I would finally be able to get through again. This didn't happen every day, but it always took the same pattern when it did. Then yesterday the problem began about 11:30 am, and it was 10:30 pm before I could send mail again; and this morning I lost the ability to send mail out about 9:15.

So I phoned my ISP, and found the problem did not lie in their server as I had expected (Entourage was giving me the standard message "An operation on the server timed out. The server may be down, overloaded, or there may be too much net traffic.//Mail could not be sent.//Error: -3259"). The fault is not in Entourage itself, either; Mail is blocked the same way, and the timeout also occurs when I telnet to the SMTP server in Terminal (I can telnet to the POP server just fine). The problem remains when I disable Norton Personal Firewall, NAV, and Snort.

The trouble seems to be confined to my machine. I am cabled to an AirPort Extreme base station; our network includes another two eMacs and a PC, all connected wirelessly. I tried to telnet from one of the other Macs and had no trouble.

So what can I do to discover what's blocking port 25, and how to unblock it? What haven't I thought of? (Probably something obvious...)

TIA, Jeff

PowerMac G4 (AGP Graphics), Mac OS X (10.4.3), 450 MHz upgraded to 1.2 GHz; 1.5 GB RAM; 1 Mb/s

Posted on Nov 23, 2005 4:20 AM

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Answer 1

a brody

Level 10

85,314 points

Nov 23, 2005 5:50 AM in response to Jeffrey Dean

Try using port 2626 or 587 instead. Some ISPs won't block those ports while blocking port 25.

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Answer 2

Jeffrey Dean Author

Level 1

40 points

Nov 23, 2005 7:04 AM in response to a brody

Sorry, that's not the trouble -- the advisor from my ISP specifically wanted me to use port 25, and anyway those ports are similarly blocked when I try to telnet. The problem is certainly on my machine and not at the ISP, nor even at my AirPort Extreme.

Thanks for trying!

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Answer 3

a brody

Level 10

85,314 points

Nov 23, 2005 7:06 AM in response to Jeffrey Dean

Try uninstalling Norton Personal Firewall. Others have had trouble with it as well. Just being on the machine can sometimes be a problem.

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Answer 4

Jeffrey Dean Author

Level 1

40 points

Nov 23, 2005 7:57 AM in response to a brody

That's good advice, but I'm stymied: whenever I try to run Norton Uninstaller, it gives me a nasty message "UNKNWON_ERROR" [sic] many times repeated, and nothing has been removed. I'm hesitant to remove files manually without knowing what support files to get rid of besides the application(s).

But having tried again before replying, I can now add to the characterization of the problem. When Norton Uninstaller asked me to restart, I booted in Single User mode and ran fsck. A sh*tload of orphaned temp files showed up and had to be cleared. When I got back into normal mode, the fault had cleared (no surprise, really).

So the question becomes this: What process running on my machine is breaking down so as to block me from sending SMTP?

A further symptom turns out to be that, although my machine was properly connected to the internet through the AirPort Extreme base station, and was getting a good DHCP lease, the base station itself was inaccessible from AirPort Admin Utility. (I looked because I wanted to see whether there could be anything blocking my machine alone from that end.) That too now works.

Anyway, I now know how to recover when the SMTP problem arises. But that's only half the issue -- I really want to know what's going wrong in the first place, so I can prevent it happening in the future.

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Answer 5

a brody

Level 10

85,314 points

Nov 23, 2005 9:06 AM in response to Jeffrey Dean

Contact Symantec tech support and let them know you are getting this error and ask them which files to remove manually.

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