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RedHat 6.2 - wow!


2007/09/14

Today I meandered down state to answer a distress call on a Linux box exhibiting a number of baffling symptoms (well, they baffled me on the phone at least). Suddenly, after "changing nothing" (of course), the system:

o Was very slow to login
o No Windows machine could print to a certain printer
o Messages about "neighbor table overflow" were sometimes appearing on the console
o "broken pipe" messages also came up now and then..

Most of this seemed to point to networking problems, though it seemed odd to me that if it was truly this broken that it was working at all.. I mean "slow" to login? I would have thought "can't login at all". And only one printer not working? Seemed odd, so I drove on down.

Imagine my delight to find a RedHat 6.2 box. Oh well, I know they need to upgrade this puppy, but I figured I could at least try to fix the thing.. so I dug in..

Just to get started, I populated /etc/hosts with everything possible:

192.168.1.1 host1
192.168.1.2 host2
..
192.168.1.254 host254

That fixed the slow login problem, but it shouldn't have, because this had "just started", and it had obviously always been unpopulated. Maybe it had been getting resolution from the router before? Possible, but it very deliberately did NOT have any router info - no access to or from the Internet for this guy (good idea, considering its age). So I don't know, but that fixed that, so I next looked at the printer issue.

That turned out to be a shared printer on a Winows machine. The owner explained that someone had changed the name. and yes, that was true, but it was also noted that it had stopped working prior to the name change.. ahh, so this has been going on a while and has nothing to do with the other problems.. ok.

Well, that was easy to fix: someone put a Computer Associates firewall on the machine sharing the printer and set the local network zone to "High Security", thus making it impossible for it to join any network activity other than looking at other machines. I adjusted that and of course now it could print.

The "broken pipe" messages were coming from Samba, which seemed to be working, though throwing out lots of complaints about the machine with the Firewall. These complaints had apparently made its logs too large, and it couldn't write more.. I don't quite follow that, as the logs really weren't that large, but I stopped Samba, removed the logs, and restarted it.. Samba was much happier now that the firewalled machine was willing to talk to it, so that's probably fixed too..

That left the "neighbor table overflow". That's probably a localhost problem, but I couldn't get it to happen.. maybe it will come back, maybe not..

Obviously they do need to upgrade, but at least this stuff is fixed..



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Sat Sep 15 13:56:02 2007: 3125   BigDumbDinosaur


The "broken pipe" messages were coming from Samba, which seemed to be working, though throwing out lots of complaints about the machine with the Firewall. These complaints had apparently made its logs too large, and it couldn't write more.. I don't quite follow that, as the logs really weren't that large, but I stopped Samba, removed the logs, and restarted it.. Samba was much happier now that the firewalled machine was willing to talk to it, so that's probably fixed too.

You should check smb.conf for the presence of a max log size parameter. max log size limits the log.smbd and log.nmbd files to max log size KB (100 is a good size for an active system). Without a max log size limit, these logs will become huge and will definitely bog down Samba.

Also, set the log level parameter to zero (numeral zero) so only errors are logged. Anything higher will rapidly fill the logs with mostly unimportant chatter.



Wed Sep 26 01:42:43 2007: 3160   sk43999


Why "wow"? I still run RH6.2 on my home desktop. Works great! What update?

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