Archive for April, 2011

R1Soft CDP scheduler issues

Thursday, April 28th, 2011

After spending quite some time with R1Soft support investigating some bizarre issues where the CDP 2.0 scheduler was skipping over some tasks seemingly at random, we eventually discovered that the issue was caused by setting the e-mail reporting task to run every minute. Decreasing the frequency of this task allowed all scheduled CDP tasks to run as normal.

R1Soft are now investigating what causes these issues with the CDP 2.0 scheduler when tasks are set to run every minute. The option of running every minute is available through the CDP interface and R1Soft were unable to explain why setting the e-mail notifications to run every minute would intermittently break the scheduling of both the e-mail notifications and other scheduled tasks such as the all important backup processes!

Missing kernel initial RAM disk with SolusVM and Xen

Thursday, April 28th, 2011

If for any reason your /boot/solus-vmlinuz symlink as well the /boot/solus-initrd.img initial RAM disk are missing or incorrect in Dom0 on one of your SolusVM Xen slaves, then you can force SolusVM to regenerate them using the latest Xen enabled copy of the kernel installed on the server using the following command in Dom0 on the slave:

php /usr/local/solusvm/includes/xenkernel.php

This not only re-creates the /boot/solus-vmlinuz symlink to the appropriate vmlinuz file, but also builds the necessary /boot/solus-initrd.img initial RAM disk to boot your DomU machines.

Of course, if you are using PyGrub then you don’t use these files in Dom0 🙂

RouterOS slow learning BGP routes with Winbox open

Thursday, April 28th, 2011

After banging my head against a wall waiting for a RouterOS powered router to re-learn the 330,000 routes that currently make up the global routing table, I was surprised to find that seemingly Winbox slows the learning of BGP routes to a crawl. Closing Winbox allowed the router to process the entire global routing table in the normal minute or so, including passing through some complex filters.

It would seem that in RouterOS 4.x at least, the router is pushing details of all learned routes to any Winbox clients connected and slowing itself to a crawl in the process. I haven’t had a chance to verify if this affects all versions of RouterOS 4.x yet or test it on RouterOS 5.x

Preventing backscatter on aliased domains in Zimbra

Tuesday, April 5th, 2011

By default, an aliased domain in Zimbra will accept all e-mail at SMTP time and then bounce a message later if it is unable to delivering it after carrying out the aliasing. This generates backscatter, which can be abused and even lead to your mail server appearing on some blacklists. Luckily, since Zimbra 5.0.12 there has been a way to fix this; just su to the zimbra user and run:

zmlocalconfig -e postfix_enable_smtpd_policyd=yes
zmprov mcf +zimbraMtaRestriction “check_policy_service unix:private/policy”
postfix stop
postfix start