At work, we have many Unix and Linux systems, so we use NIS to coordinate the authentication and authorization of users. One of our Unix groups has so many members that the older Unix systems can’t “see” them all. So, we split up the membership into a set of entries in the /etc/group file that […]
Turns out that for some cases, awking is much, much faster than grep. Just now, I wanted to know how many unique MAC addresses appeared in our DHCP server’s log file asking for a lease but not getting it. There are a few ways to skin this cat. What’s interesting is that some ways are […]
I’m building a cluster of 25 machines at work. Trying to get the Infiniband stuff to work on them – a dev found an annomoly in his benchmarking numbers and asked me to verify his work and look for trouble and so – I did. While I was doing it, I found some other users […]
Just built a cluster of 25 Dell systems for our developers. These are Dell 1435SC systems, each with a pair of Dell 1435SC and 8 GB RAM. We installed openSUSE 10.3 on them all, added the Ganglia gmond and also the OpenIB infiniband successor OFED. Handed them off to our developers to certify and they […]
When I saw this, I thought of a colleagues recent experience with his client’s servers being taken over through a weakness in VNC. It was a pretty scary experience for him and his client – everyone in our Upper Valley Freelancers group tried to help and the mail flew fast and frequently for a few […]
Plagued by these messages in your Linux server’s kernel log – kern.log? Finally tracked down a reasonable explanation this morning. Seems a bug was introduced in the kernel back in 2.6.8 and it causes, among other troubles, this error message: Jan 17 12:30:13 iml kernel: TCP: Treason uncloaked! Peer 134.48.120.88:3832/80 shrinks window 3881756777:3881761622. Repaired.Jan 21 […]
If I want to rename a user from “Mike Diehn” to “mdiehn” Log the user out. Log in as an Administrator, preferably in the realm in which the user account is defined rather than simply in the local computer realm. Manage Local Users and GroupRename the user account, maybe fill in the Full Name and […]
Fairly common practice from Sendmail and even Postfix setups is to use an alias in /etc/aliases or some such file to route mail for a certain address to the “bitbucket.” Like this: spamtrap: /dev/null Well, put that into /etc/aliases on a Debian system running Exim4 with a stock config and it won’t work. I learned […]
SO long ago it’s lost in the fog of burnt neurons, I made MRTG do one-minute polling and now I have to do it again….. ugh…