DHCP Issues?

Discussion in 'Linux Networking' started by Edwin Humphries, Mar 21, 2014.

  1. Edwin Humphries

    Edwin Humphries New Member

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    Hi,


    I manage (for heritage purposes, not because I want to) a CentOS-based billing router for a resort; the router manages a network of 40 guest rooms and conference rooms, managing client connections and monitoring usage and billing for it. The customer has recently complained about excessive slowness in response when managing the accounts on the system via a web interface (apache/php/pgsql). I don't see much unusual activity via top.

    The router was originally designed in the days before ubiquitous smart-phones and tablets, and it made me wonder about DHCP activity: what I found is lots of current DHCP leases (see the attached file)dhcpd.leases.txt.tar.gz; I also checked /var/log/messages, which was overflowing with DHCP traffic (see the attached file)dhcp_traffic.txt.tar.gz.

    I'm wondering whether this sort of DHCP traffic is normal in a such an environment, if it could be the cause of the perceived slowness, and - most important, what to do about it?

    --

    Regards,
    Edwin Humphries

    Attached Files:

  2. ryanvade

    ryanvade Administrator Staff Member Staff Writer

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    If the server is being overused due to the DHCP overflow then it will definitely cause issues. What are the specs of the server?
  3. Edwin Humphries

    Edwin Humphries New Member

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    It's not really a server, just a customer designed router: specs are:
    Operating system CentOS Linux 5
    Kernel and CPU Linux 2.6.18-53.el5 on i686
    Processor information VIA Nehemiah, 1 cores
    Running processes 631
    CPU load averages 14.64 (1 min) 17.23 (5 mins) 18.62 (15 mins)
    CPU usage 70% user, 29% kernel, 0% IO, 0% idle
    Real memory 471.70 MB total, 292.68 MB used
    Virtual memory 509.87 MB total, 6.38 MB used
    Local disk space 31.09 GB total, 4.29 GB used
  4. ryanvade

    ryanvade Administrator Staff Member Staff Writer

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    hmm. I assume that the server did not always seem this slow? The traffic must have increased and that is when the slowness occurred. Perhaps as the increase of DHCP requests increased the server started to have a harder time keeping track of the leases. The system does not seem too overloaded. A one core system is not unheard for this kind of work. CentOS 5 is not very old; not officially supported any longer but not old.

    I think some disk cleaning may help. Going through the DHCP settings to find any unnecessary settings. The rest of the network may need some looking over also.

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