DNS DoS Attack
Looks like one of my name servers (CentOS 5) gets a lot of malicious queries. The cpu load is constantly about 3 %. I put on stricter limits on who is allowed recursive queries, but this does not...
View ArticleMonitoring VM Loads
I am using CentOS 5, and kvm virtualization.My VM stack (about 10 v-machines) now often gets painfully slow, probably because of IO limitations. How could I find out where the load comes from?virt-top...
View ArticleCentOS 6 KVM Guest On CentOS 5 Host
I have a KVM virtual stack of about 10 v-machines on a CentOS 5 host. Now the perceived efficiency of the whole virtual stack has dropped. The load averages may be low, but still the systems sometimes...
View ArticleAmavisd Start
This is CentOS 6. Why can it be that when I try to run /etc/init.d/amavisd start … I get this error: Starting Mail Virus Scanner (amavisd): Config file “/etc/amavisd.conf” is inaccessible: Permission...
View ArticleMemory Leak – How To Investigate
My web & name server runs out of memory from time to time, to the point where it’s completely unresponsive to anything. At that point reset is the only alternative. (Or, as this is a virtual guest,...
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