timed out waiting for a valid DHCP server response

Discussion in 'Linux Networking' started by Matthew Weymar, Sep 26, 2003.

  1. Hi,

    Booting up RH w/ 2.4.18-10smp kernel for the first time in a long
    time, in a new and different network than the one to which this box
    used to be connected - and in which DHCP worked just fine.
    Specifically, I'm on a LAN that's connected to a ZyXEL Prestige 600
    Series DSL Modem.

    /var/log/syslog reveals: "dhcpcp[pid]: timed out waiting for a valid
    DHCP server response"

    DHCP works in Windoze, so the hardware's fine.

    What could be wrong? and how can I try to fix it?...

    NB - I have found two people who've described having this problem - or
    a problem or problems very much like it - and then its apparently
    resolving itself without any change to their configuration.*

    I get the basic idea of DHCP, but "the basic idea's" not quite enough
    to help me understand what's going on for these people - and what may
    well be going on for me - much less does it suggest anything I can
    *do* about all this(!)

    Finally, I'm no conspiracy theorist, but I just ran across the
    following thread - http://www.knoppix.net/forum/viewtopic.php?t=2164,
    under the heading "Evidence WinXP 'security updates' may break Linux"
    - which, as convoluted and inconclusive as it may be, prompts me to
    wonder whether Windoze may have done something (to the NIC's eeprom?)
    to cause the problem.

    Any thoughts, suggestions, requests for more info. will be most


    * C.f. http://www.linuxquestions.org/questions/archive/3/2002/05/4/21462,
    and http://groups.google.com/groups?hl=&rnum=1
    (if that URL works - it's awful long.)
    Matthew Weymar, Sep 26, 2003
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  2. Matthew Weymar

    Bit Twister Guest

    need changes or your dhcp client is using a stale file which needs to
    be deleted.
    Bit Twister, Sep 26, 2003
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  3. Inconclusive, at best...
    Log files ? Run dhcpcd manually and use the -d flag.
    Run "pump" - does that get you an IP ?

    Try increasing the timeout in dhcpcd.conf - since that's the error, you
    might have started there.
    (Though I doubt it - the dhcp timeout is pretty long as it is - up to
    downright annoying in Windoze...)
    Which does not help any, does it ?
    Read the documentation for dhcpcd, and the docs for the modem/dchp server.

    Does it say, specifically, how it expects the clients to behave ?

    Windows apparently working tells you less than nothing - 50% of the
    protocols as implemented by Micro$haft are not RFC-compliant or just plain

    Yes - the only part needed to get to the article is the "threadm=" ID.
    Leave off the rest.
    Jeroen Geilman, Sep 27, 2003
  4. DEVICE=eth0

    These seem pretty innocuous, do they not?...
    Per 'man dhcpcd', I add "local0.* /var/log/dhcpcd.log" to
    /etc/syslog.conf, reboot (same problem) and check the dhcpcd.log file,
    where the only entry refers to the timing out issue. I then run
    -d". I get:

    dhcpcd: MAC address = xx:xx:xx:xx:xx:xx

    and then eventually a prompt. Sadly, eth0 is still without an IP

    Checking /var/log/dhcpcd.log, however, reveals:

    localhost dhcpcd[pid]: broadcasting DHCP_REQUEST for 192.168.x.x
    localhost dhcpcd[pid]: timed out waiting for DHCP_ACK response
    localhost dhcpcd[pid]: broadcasting DHCP_DISCOVER
    localhost dhcpcd[pid]: timed out waiting for a valid DHCP server

    Interestingly my router's IP is: 192.168.y.1(!), so it seems that
    right that there's something "stale" in there. "But what? where?" I am
    asking myself....

    After *much* poking around, I have come across a post by Brian Cluff
    another list in which he mentions deleting the
    /etc/dhcpc/dhcpcd-eth0.info file, and "getting an IP without a hitch."
    Opening this file up and seeing my "bad" 192.168.x.x IP filled me with
    optimism - that deleting this file would put me in business,
    Alas, 'tis not the case.

    After deleting /etc/dhcpc/dhcpcd-eth0.info, /var/logdhcpcd.log
    (following 'dhcpcd -d') indicates that I'm still "broadcasting
    DHCP_REQUEST for 192.168.x.x."

    I figure dhcpcd is picking this up from /etc/dhcpc/dhcpcd-eth0.cache,
    and so I delete that, run 'dhcpcd -d' again and find that
    /var/logdhcpcd.log now includes only the latter two of the four lines

    localhost dhcpcd[pid]: broadcasting DHCP_DISCOVER
    localhost dhcpcd[pid]: timed out waiting for a valid DHCP server

    I try creating a new /etc/dhcpc/dhcpcd-eth0.info, substituting
    192.168.y.x for 192.168.x.x, but I get these same two lines (above),
    only these two lines again.

    Now I search the net on "new /etc/dhcpc/dhcpcd-eth0.info" and see that
    perhaps I should have run "ifdown eth0" and then "ifup eth0". I delete
    /etc/dhcpc/dhcpcd-eth0.info again, and run ifdown & ifup. Both
    operations fail.

    I find a LinuxPlanet.net tutorial on "xDSL and Linux: Go Speed Racer!"
    Being a fan, I try the script they suggest (see below). This does
    nothing for me. Still no IP address.

    Pausing to take a breath... hoping for more suggestions....

    Addendum: In light of Jeroen Geilman's reply to my original post, I
    try 'pump -i eth0', and find that it does not work.

    I think that one of my problems is that since DHCP fails on startup,
    is not properly recognized (because it doesn't have an IP?...) I don't


    From http://linuxplanet.com/linuxplanet/tutorials/1454/4/:

    # Name: renet
    # Author: Nicholas Donovan <)
    # Function: resets the IP by bumping a request from DHCPCD
    # Revisions:

    # remove the old information
    rm /etc/dhcpc/dhcpcd-eth0.cache -f
    rm /etc/dhcpc/dhcpcd-eth0.info -f

    # kill the runtime PID reference
    rm /var/run/dhcpcd-eth0.pid -f

    # request a new IP from server...
    echo "making new DHCP request..."
    # I added the '-d' argument - unnecessarily??? -- MDW
    /sbin/dhcpcd -d
    sleep 3

    # if changed properly tell it then pipe to log file...
    echo "(dhcpcd) IP address changed to $1" | logger

    # Display the new IP
    echo "Your new DHCP address is:"
    /sbin/ifconfig eth0

    # End of Script

    Simply chmod 744 this script and place it into the /sbin directory.
    Matthew Weymar, Sep 27, 2003
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