What Goes Around, Comes Around

April 12, 2006 by Eric Richardson

Someone just used an IM bot to message me. It looks to have been seeded with one bit of seemingly sentient information (the initial message mentioned that I was getting married), and then the bot took over from there. The person who sends the bot gets to sit back, watch the traffic, and hopefully laugh as they trick someone into thinking they're speaking to a real person.

I don't know who sent it, so I'm not sure whether or not that person realized I wrote a bot to do the exact same thing. And I did it back in December of 1999. HoserAIMa spoke via Net::AIM and backended to Eliza. I had a console where I could inject messages into the conversations I was watching to pull people back right when they were starting to get frustrated enough to give up on the bot (or had started to see through its ruse).

Nice to know that in six years nothing has changed. — Continue Reading...

The Joys of Fat Traffic

April 12, 2006 by Eric Richardson

Now that we're running our email on a server where we pay for bandwidth, I've realized I need to become a lot more conscious of how people use email. There's no excuse for busting up our 95th percentile just because someone's downloading or sending attachments.

This morning I saw a couple periods of pretty constant traffic into and out of the server, and judging by how the server bandwidth graphs correspond to the interface stats on the router, it seems that it's pretty much all traffic from the office. It's not a lot of users; just "fat" traffic from a few of them (attachments, perhaps).

Complicating matters is that the tools I would normally use to check out network conditions are all on Linux, and here at work it's all Macs. — Continue Reading...

Never a Clean Transition

April 10, 2006 by Eric Richardson

We're moving email service here at the office, from ISP hosted mail to our colocated server. Friday I set up the new accounts and around 5:30 or so I switched MX to point to the new address.

That meant that I knew all weekend there were going to be issues when I walked in the door today.

It's a fact of life: you move services between disparate hosts and something's not going to work right.

In my case I found two issues:

  • I'm using qpsmtpd as my SMTP server, and all my test messages had been small. Because of that, I didn't know my spool dir was set up incorrectly and was unwritable by the mail daemon.

  • courier-imap defaults to setting MAXPERIP to 4 connections per IP address. When everyone fired up email this morning errors started popping up and nothing showed in the logs. Once I figured out what was up (though really I didn't... pcg quessed it) it was an easy change.

So after a bit of a hairy morning I think everything's running smooth now.

Fun with OS X and the Firewall

April 04, 2006 by Eric Richardson

As I mentioned that I would a few days ago, I moved our office network from a little Netgear DSL router to letting the Xserve do NAT and firewall.

That went ok, but I was really frustrated by the process of using Apple's firewall configuration through the Server Admin. Fundamentally my issue was that Apple's utility wants to deal in rules defined by IP spaces, and that's just not proper. When dealing with a router type host, it seems clear to me that you need to define your rules based on interfaces. While it's possible to do this in the Advanced settings, that's not at all easy to figure out (in fact I think it would be easier for anyone using that to simply write their own rules). — Continue Reading...

su: who are you?

March 31, 2006 by Eric Richardson

I'm still getting the NAT stuff set up on the xserve, and haven't even touched traffic shaping yet, but I was pretty amazed by how I managed to break things in the process of setting up a stateful firewall on OS X.

Apparently if you forget to allow connections via localhost, OS X sort of loses it. And I mean this to the extent that when logged in as admin, you no longer have an identity. su asks you who you are.

I guess I hadn't considered the ramifications of directory authentication, even when you're not doing remote stuff.