Wed, 02 Jul 2003

First flat

I left the office at 5:15. At home, we've been working on a house painting/repair project for weeks. Cheaply built in the mid-70s, the house needed poorly sealed windows, weather damaged fascia boards, and a dry rotted false chimney replaced.

Christopher was scheduled to work 6 PM to close at his summer job. If I made it home by 5:30, that would get me 15 minutes to get the heavy panels for the false chimney I assembled yesterday onto the roof before he left for work.

I carried the bike up the outside stairs from the basement before realizing the back tire was flat. Sigh. Oh well. Back inside to fix my first flat of the year.

Halfway through the tube replacement, I was paged. Had to take a support call.

Now, this particular user's initials are TDS. He's my employer. (And if I've exceeded the boundaries of his sense of humor, that last statement may only be true in the past-tense!) By force of authority, TDS reverses the troubleshooting process. Instead of starting with the most likely problem (user error), and working forward (user's desktop computer, …, mail server), we have to work in reverse.

The mail server is down.

I check the server. It's up and running. I can connect from inside. I ssh to an external system and try from there. "The server is up and running and it is accessible from the outside," I report.

We go from there to checking server logs for authentication errors, firewall rules, and eventually, packet sniffing to watch the inbound and outbound packets on port 25. Nothing.

Perhaps your ISP is now blocking port 25 access, I venture. Testing that hypothesis, I have him check various other mail servers with telnet to port 25. No luck. We seem to be confirming the theory.

I have him try the POP3 port. If his ISP has blocked port 25, we will have to use their SMTP server for outbound mail. He should still be able to retrieve mail directly from the company's mail server, though.

No luck. Then, in the midst of failed attempts to connect to other servers, I see a series of packets exchanged between his IP address and our POP3 server.

What did you do differently, I query.


Hmmm. Go see if Brenda can receive mail. TDS runs a small home network, and Brenda, his better half, has a mail account.

Sure enough, Brenda can send and receive mail, and it was a periodic mail check I had seen with tcpdump.

Well, obviously, it's your system, I say.

How can that be?

Are you running Windows? Yes. I blame everything on Windows. It's easy, and usually correct.

No, he says, I'm running Linux. An outright lie, of course. If he was running Linux, we wouldn't be having this conversation. First, Linux wouldn't be behaving this way. Second, any user capable of running Linux could troubleshoot this problem without my assistance. No offense to the hand that feeds me. <g>

Well, then, it's a hardware problem. What's that line? The first liar doesn't have a prayer — I learned it from TDS.

Are you running a virus scanner?

Yes, of course. I updated it today.


"Let's see. It's supposed to be scanning incoming and outgoing e-mail, but there's an error icon."

A config change (unadmitted, of course) and reboot, and he's receiving mail, again.

And I make it home by 7. Just enough time left to haul the components for the false chimney up on the roof without Christopher and assemble them before an advancing thunderstorm chases me off the off.

Damn, that was a pretty sunset behind those lightning bolts from my vantage point on the roof. <g>

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