Difference between netstat & rndc status
chris.p.buxton at gmail.com
Sun Jul 3 15:01:13 UTC 2011
On Jul 3, 2011, at 12:03 AM, Bind wrote:
> Hello Admins
> When i run :
> #netstat -an |grep udp |wc
> it returns a number which is lower than the output of rndc status recursive clients.
> what is the difference between netstat -an |grep udp |wc(open udp ports to dns server) and amount of recursice clients in the rndc status command?
> I thinked they should present the same value? doesnt it?
No. That would be true if queries were sent over TCP. UDP does not work like TCP.
With normal queries, when the message comes in, the connection closes. Some time later (hopefully not much later), a new message goes out to return an answer to the client. The only time you'll see an open connection like this with netstat is when named has not yet fully read the query message from the network receive queue.
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