Linux tip of the day

If you have a busy server, check how big a log file is before trying to open it with your favourite light weight text editor.

Made this mistake today.

One of the mail servers I run for a client gets some email, but gets an horrific amount of spam, and attempts at spam. In fact it looks almost like a concerted denial of service attempt.

I greped the logfile to see how many noqueues it had. 164,000 in 5 days. That is just silly. I then tried to open the logfile to see how many lines it had in it and lost the server.

I almost got in far enough to kill the process but not quick enough. The server had to be rebooted.

The mail log was over 1GB in just 5 days. This mail server only handles one domain.

Just how are ISP's supposed to keep 6 months records of emails? They manage thousands or hundreds of thousands of domains. The log files must grow at a huge rate.

NPI Errors

Every so often you get one of those calls...

Caller "Hi, I can't get on the Internet"

Me. "I see. Can you click start, then run, type in cmd, then press return. That should get you up a black box, yes? Good. Type in ipconfig and then press return. What does it say?"

Caller "It says blah blah blah ... Media disconnected"

Me "You couldn't plug it into the network please?"

An NPI error is as you may now have guessed a Not Plugged In Error. If I had a Pound for every one, I'd have quite a few pounds.

Aarrghhhh Microsoft!

I have been installing Novell OES, with a few glitches thrown in on the way (which will be the subject of future articles) when I came across another problem I just did not need!

There I am, everything just about tickety boo, when one machine suddenly can log on to the network for toffee.

Obviously a problem with the Novell client for NetWare or a server issue. maybe the lack of slp or similar.

Well, after a lot of fiddling in the direction the error pointed I then noticed that once logged on to the work station only option, the machine would just sit there not bringing up the desktop until I pressed ALT + CTRL + DEL when the desktop would appear. It did not matter how long I left it or didn't.

Odd.

So then I tried to log on to NetWare. Well I got it to authenticate but the logon script just hung. Hmm...

Opened task manager and killed some processes. (iTunes for example). Nothing. I then stopped the print spooler, spoolsv.exe. It sprang into life!

Printing still worked because the spooler would restart and then behave although it then took up 10MB of ram (this just to send jibs to printers, and when it is doing NOTHING).

Very irritating.

Bad Microsoft. Very bad Microsoft.

Still I have a work around, now i just have to fix the spooler process. I looked at this article, but it's advice did not seem to fit. I will look further in the morning.

Passing Bt Engineer scuppers network!

Ages ago i set up a nice little server running Arch Linux, with a custom compile of Samba, running very nicely thank you very much.

I set up Bind, DHCP, CUPS, and jut about everything else so that as far as the users running Windows were concerned they may well have been attached to a Windows server (except of course it is rock solid)

Not much bother there then.

Until one day the BT managed router connecting said network to the interweb thingy ceased to function (I presume it was involved in sexual intercourse).

So along came the BT man, with his nice shiny new router to put in place.

By the time he left you could either get on the Internet or the server, but not both.

What he had done was to make his router a DHCP server (as in giving out network addresses and configuration information) with different network information as well. The result was that if your PC got its information from one then it was on the Internet and if it got it from the other then it could get on the server.

All the BT engineer had to actually do is turn his brain on, and query any machine for it's network settings. That would have told him the IP address that he had to set his router to, and to turn DHCP off. Would have taken 2 minutes to find out, and anther 2 to set up the router, as opposed to the several hours he did spend going around in circles buggering things up.

Always remember when on an unfamiliar network, that it helps to check out some very basics before you try to unnecessarily try to reconfigure everything.