Zulus Tips

Such simple task, like moving ejabberd from one server to another, costs me about one hour of time. Moving procedure very good described here, and everything goes smoothly, untill i get following error:

RPC failed on the node restore: nodedown


I have read a lot of docs, blogs, etc. There was some references regarding ejabberdctl tuning on FreeBSD, but unfortunately without any details. And i have found solution myself.

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Alexander Motin has implemented replacement for proprietary MPPC library. Code based on Jan Dubiec Linux patches.
But due to patent restrictions this code can’t be included to system tree. You can try it on your own risk.

Original thread

Trying to keep server live under huge DDoS. After some time following message appeared:
ipfw: install_state: Too many dynamic rules

Problem solved after i change following sysctl value:

net.inet.ip.fw.dyn_max
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Some time ago i have found very interesting patch for FreeBSD kernel. Patch was originally posted by Andre Oppermann in freebsd-current maillist. That patch allows dynamically change TCP send and receive buffer sizes. However Andre posed version only for FreeBSD CURRENT, so i have make note to try patch as soon as i have chance to install CURRENT. But today, my colleague told me that he found version for 6.x, and i have spent last few hours for patching & testing. As i wrote before, patch allows dynamically change TCP buffer size. Using that patch you can save a lot of kernel memory, because you don’t need to set big values for socket buffers. TCP session will start with a small buffer size and grow to match network conditions. Andre showed about 1000% better performance in his tests.
Below you can find my test results.

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I have a new favorite extension for FireFox - Firefox AS Number

Plugin displays a lot of information including AS Number, BGP Prefix, RIR. Plugin can be very useful for network administrators.