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We are regularly getting UDP errors in one of our DHCP server with a continues increase in pattern, see below the UDP errors

(delay of 10 seconds)
634822 packet receive errors
634893 packet receive errors
634959 packet receive errors
634961 packet receive errors
634976 packet receive errors
634989 packet receive errors

see one example of netstat -su

IcmpMsg:
    InType0: 3036
    InType3: 792918
    InType8: 28325
    InType11: 41
    OutType0: 28325
    OutType3: 19805
    OutType8: 77310
Udp:
    3145378 packets received
    20480 packets to unknown port received.
    636419 packet receive errors
    2899799 packets sent
RcvbufErrors: 173
UdpLite:
IpExt:
    InOctets: -1625660786
    OutOctets: 1622539094

background - IPAM (efficient IP) web application is a front end of DHCP server OS Distribution - Ubuntu 12.04.2 LTS Memory - 36G

Please guide us with the next step for resolution.

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1 Answer 1

My uptime is now more than 23 hours and I have no UDP receive errors. I see that you are getting between 1-7 errors per second--a lot.

UDP packet receive errors probably represent something mangling the data in those packets. There's an optional checksum in UDP packets that are used to detect bad UDP packets.

Packet mangling could normally happen anywhere on the Internet, but DHCP packets should only be coming from your own LAN. On the other hand--that's a lot of errors to be coming only from DHCP. DHCP is only used when systems boot, and usually once every few hours per computer--not seven times a second. What else are you running on this server?

I would check the network connection for the computer in question, maybe swapping out the network adapter and the switch port to which it is probably connected to see if that helps.

Another thing to try is to use the combination of tcpdump and wireshark to identify what those bad packets are--something strange may be going on.

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