DHCP Server not able to handle the Traffic

sthaug at nethelp.no sthaug at nethelp.no
Sun Apr 26 13:22:01 UTC 2009

> I ran the commands on the Server and I got the following results. Can
> you please help me in pointing the root cause for packets getting
> dropped

Difficult, given the lack of information. First, this is a Linux system.
I'm not a Linux expert, you should consult somebody who knows Linux well.

Second, running these commands once or for a few seconds is not enough.
You need to establish a "baseline" - what is the normal load on your
system *without* dhcpd, both for short and longer term intervals. Then
look at the load *with* dhcpd, paying lots of attention to disk I/O
operations. Blocks written per second is highly relevant, so is the
percentage of time spent in iowait.

Third, there should be a way to get statistics about UDP packets being
dropped by the operating system (due to full buffers etc). I don't see
this directly in the netstat output you've shown. Maybe this is the
"6311155 packet receive errors" - somebody with more detailed Linux
knowledge should be able to tell you. Is this counter incrementing as
you run dhcpd?

Fourth, as somebody else pointed out, you need to make sure that your
syslog is not synchronous. Have you done this?

Steinar Haug, Nethelp consulting, sthaug at nethelp.no

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