Technical - Spheron1

April 15, 2010

MySQL system tables and blank entries in the Host column

I discovered some interesting behaviour under MySQL 4.1 recently (I know it’s old, but it’s not within my power to upgrade it) whereby empty entries in the Host column of the users table under the mysql system database were causing all remote (i.e. TCP and not socket) connections to be refused with a message saying “Host ‘1.2.3.4’ is not allowed...

Technical Comments: 0

April 11, 2010

Zimbra anti-spam improvements

The built in Zimbra anti-spam system is quite a neat bundle of Amavisd-new, SpamAssassin and ClamAV with some fancy automated ham/spam training based on messages being moved in and out of a “Junk” mailbox under each user’s account, but it lacks a few nice to have extra features. Luckily, it’s quite easy to enhance the Zimbra Amavisd and SpamAssassin with...

Zimbra Comments: 2

April 9, 2010

iPhone OS 4.0

I’ve been playing with iPhone OS 4.0 on my iPhone 3GS since it became available to developers after the press conference yesterday and so far impressions are good – it has broken the Worms app which won’t even launch any more 🙁 but everything else seems to be fine. Multitasking pause/resume of apps seems to work quite well and is...

iPhone and iPad Comments: 0

April 8, 2010

Sharing one keyboard and mouse between several Macs

If you have multiple computers, each with it’s own monitor then it can get really confusing having multiple keyboards and mice in front of you, not to mention somewhat disrupting to your workflow every time you have to change between them and reposition your hands appropriately. Having a KVM switch can help with this, but only lets you use a...

Mac OS X Comments: 0

April 7, 2010

Detecting brute force attacks on Zimbra with zmauditswatch

Zimbra 5.0.11 introduced the zmauditswatch script which notifies a specific e-mail address of a potential brute force attack if certain conditions are met. This is disabled by default and the documentation to enable it isn’t particularly clear, so here is a quick run through: zmlocalconfig -e zimbra_swatch_notice_user=admin@domain.com zmlocalconfig -e zimbra_swatch_ipacct_threshold=10 zmlocalconfig -e zimbra_swatch_acct_threshold=15 zmlocalconfig -e zimbra_swatch_ip_threshold=20 zmlocalconfig -e zimbra_swatch_total_threshold=60 zmlocalconfig...

Zimbra Comments: 0

April 2, 2010

Nominet Automaton bulk modify

The bulk modify feature of the Nominet Automaton can be a real time saver when you need to update a load of domains in one go. For example, I just used it to add a tertiary name server to a load of domains under the FREETHOUGHT tag. To make sure that I only updated domains using the Freethought nameservers, I...

Domains and DNS Comments: 0

March 28, 2010

DomU kernel panic under Xen with R1Soft CDP agent

I ran into a weird problem on a freshly installed server today where one of the DomU virtual machines kept locking up with a kernel panic message: BUG: soft lockup – CPU#1 stuck for 10s! All of the other Xen DomU virtual machines running on the box were fine, so I was pretty sure it wasn’t a hardware bug. The...

R1Soft CDP/Red Hat and CentOS/Zimbra Comments: 0

March 25, 2010

Weirdest Linux command ever

This morning I had to run possibly the most bizzare Linux command ever whilst stripping down a CentOS server: yum remove troursers That really brightened up my day and made me smile. 🙂

Red Hat and CentOS Comments: 0

March 18, 2010

Activity Monitor in Snow Leopard

If you’re anything like me, then you like to keep your computer nice and neat and organised; this includes sorting all of my applications into categories so that they don’t clutter the place up in one big list. In Mac OS X 10.6 (aka Snow Leopard), this presents a bit of a problem as Activity Monitor can no long be...

Mac OS X Comments: 0

March 15, 2010

cPanel/WHM and yum-updatesd

In my continuing fight with yum-updatesd, I found that on servers with cPanel/WHM installed it was crashing with mysterious Python errors: root@tma03 [/etc/yum]# yum-updatesd –debug –no-fork Traceback (most recent call last): File “/usr/sbin/yum-updatesd”, line 35, in ? import dbus File “/usr/lib64/python2.4/site-packages/dbus/__init__.py”, line 1, in ? from _dbus import * File “/usr/lib64/python2.4/site-packages/dbus/_dbus.py”, line 48, in ? from proxies import * File...

cPanel/WHM Comments: 0

Category: Technical