Debian Wheezy's send_nsca and nsca 2.7.2

For the first time, a dedicated package for the NSCA agent is added under Debian Wheezy (before there was only a package which combined agent and daemon). The package version is 2.9.1 - which leads to syslog error messages in combination with a NSCA server in version 2.7.2:

1# cat /var/log/messages
2...
3nsca[30772]: Handling the connection...
4nsca[30772]: Dropping packet with invalid CRC32 - possibly due to client using wrong password or crypto algorithm?

The reason is that the new send_nsca uses a bigger fixed package size of 4096 bytes (instead of 512) - the server isn't able to handle that request. The simplest solution is compiling an older version of send_nsca. It's a good idea to choose the same version used for NSCA on the Nagios/Icinga server.

In my case it was NSCA 2.7.2. The following commands download some development tools and NSCA. Afterwards send_nsca is compiled and copied to the hard drive. In a final step, the send_nsca configuration has to be altered:

1# apt-get install gcc make libmcrypt-dev
2# links 'http://sourceforge.net/projects/nagios/files/nsca-2.x/nsca-2.7.2/nsca-2.7.2.tar.gz/download'
3# tar xfz nsca-2.7.2.tar.gz
4# cd nsca-2.7.2
5# ./configure --prefix=/usr
6# make send_nsca
7# cp src/send_nsca /usr/sbin/send_nsca
8# vi /etc/send_nsca.cfg

Let's see - it's working again:

1PASSIVE SERVICE CHECK: somehost;HW: CPU;0;OK - load average: 0.20, 0.18, 0.26

🙂

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