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Jabber

I’ve just been setting up jabber.

I followed the advice from System Monitoring on setting up ejabberd [1]. I had previously tried the default jabber server but couldn’t get it working. The ejabberd is written in Erlang [2] which has it’s own daemon that it launches. It seems that Erlang is designed for concurrent and […]

RPC and SE Linux

One ongoing problem with TCP networking is the combination of RPC services and port based services on the same host. If you have an RPC service that uses a port less than 1024 then typically it will start at 1023 and try lower ports until it finds one that works. A problem that I have […]

Switches and Cables

I’ve just read an amusing series of blog posts about bad wiring [1]. I’ve seen my share of wiring horror in the past. There are some easy ways of minimising wiring problems which seem to never get implemented.

The first thing to do is to have switches near computers. Having 48 port switches in a […]

New Net Connections

On Thursday my new InterNode ADSL2+ service was connected [1]. I needed to get a connection with a larger download cap and a better upload speed because one of my clients wants me to transfer some significant amounts of data as well as hosting some Xen DomU’s for him. Strangely InterNode couldn’t offer a regular […]

Pollution and Servers

There is a lot of interest in making organisations “green” nowadays. One issue is how to make the IT industry green. People are talking about buying “offsets” for CO2 production, but the concern is that some of the offset schemes are fraudulent. Of course the best thing to do is to minimise the use of […]

Mobile SSH Client

There has been a lot of fuss recently about the release of the iPhone [1] in Australia. But I have not been impressed.

I read an interesting post Why I don’t want an iPhone [2] which summarises some of the issues of it not being an open platform (and not having SSH client support). Given […]

The New DNS Mess

The Age has an interesting article about proposed DNS changes [1].

Apparently ICANN is going to sell top level DNS names and a prediction has been made that they will cost more than $100,000 each. A suggestion for a potential use of this would be to have cities as top level names (a .paris TLD […]

Solving Rubik’s Cube and IO Bandwidth

Solving Rubiks Cube by treating disk as RAM: Gene Cooperman gave an interesting talk at Google about how he proved that Rubik’s Cube can be solved in 26 moves and how treating disk as RAM was essential for this. The Google talk is on Youtube [1]. I recommend that you read the ACM paper he […]

Letter Frequency in Account Names

It’s a common practice when hosting email or web space for large numbers of users to group the accounts by the first letter. This is due to performance problems on some filesystems with large directories and due to the fact that often a 16bit signed integer is used for the hard link count so that […]

BIND Stats

In Debian the BIND server will by default append statistics to the file /var/cache/bind/named.stats when the command rndc stats (which seems to be undocumented) is run. The default for RHEL4 seems to be /var/named/chroot/var/named/data/named_stats.txt.

The output will include the time-stamp of the log in the number of seconds since 1970-01-01 00:00:00 UTC (see my previous […]