PIX 501 dhcp client & Charter cable system

Discussion in 'Cisco' started by Marshall Stacks, Jan 24, 2005.

  1. I recently moved from a Roadrunner cable network (San Diego) to the
    Charter network in southern Utah. My PIX 501 refuses to get an IP
    address from the Charter DHCP servers. I also have a Linksys wireless
    router and a couple of PCs running 2000/XP. Those devices get their IP
    addresses from Charter via DHCP with no problem.

    Debugging on the PIX shows:

    DHCP Offer Message Offered Address: 192.168.100.10
    DHCP: Lease Seconds: 15
    DHCP: Server ID Option: 192.168.100.1
    DHCP: offer received from 192.168.100.1
    DHCP: offer has below min lease length: 15. punt
    DHCP: offer not good enough. punt....
    DHCP: SDiscover attempt # 2 for entry:

    Looks like the PIX isn't accepting an offer below a minimum lease
    length. Which is curious because I am running 6.3(4) and a minimum lease
    length bug (CSCdz09957) was supposedly fixed in 6.3.(1). I have tried
    6.3(1),(3), and now (4) but I get the same behavior.

    FYI, I had called Charter a couple of times and they cleared out their
    mac address table for my cable modem so I don't believe the problem is
    really on the Charter side. It just seems that the PIX is being too picky.

    Any thoughts on how I might get this to work? I can put the Linksys on
    the outside and have the PIX behind the Linksys, but it's just bugging
    me that I can't get it to work with the PIX on the outside.

    Thanks
     
    Marshall Stacks, Jan 24, 2005
    #1
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  2. Marshall Stacks

    Warren Guest

    The lease isn't being offered by the Charter DHCP servers. It's being
    offered by the cablemodem. My guess is you've exceeded the maximum
    number of CPE's that can be behind the modem.

    Let me make sure I've got your configuration right. You have a couple of
    PC's connected to a router, and the router and the PIX are connected to
    a hub or switch, which is then connected to the cablemodem. In this
    configuration, the router would get it's IP address from Charter's DHCP
    servers, and then would serve the PC's internal IP address to the PC's.
    If the max CPE for the cablemodem is set for 1, the PIX would not be
    able to get another IP from Charter, and the cablemodem would default to
    an attempt to serve a short-leased, temporary IP in the 192.168.100.x
    range.

    Or maybe, since you've said the PC's are getting their IP's from
    Charter, they're not behind the router. What's connected to the router
    then? What every is behind the router would get an IP address from the
    router, not Charter.

    Whatever the setup is, the most likely reason for the cablemodem to be
    attempting to serve the address instead of the Charter network would be
    that you have too many devices already directly connected to the modem.

    --
    Warren H.

    ==========
    Disclaimer: My views reflect those of myself, and not my
    employer, my friends, nor (as she often tells me) my wife.
    Any resemblance to the views of anybody living or dead is
    coincidental. No animals were hurt in the writing of this
    response -- unless you count my dog who desperately wants
    to go outside now.
    Compare the newest tax preparation software apps:
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    Warren, Jan 24, 2005
    #2
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  3. I'm saying that connecting any of my devices directly to the cable modem
    EXCEPT the PIX works. Individually and one at a time. I am
    troubleshooting step by step- I don't have everything hooked up at once.

    Thanks
     
    Marshall Stacks, Jan 25, 2005
    #3
  4. Marshall Stacks

    Warren Guest

    In that case, each time you change what is connected to the modem, make
    sure you unplug the modem, and let it sit for 30 seconds before plugging
    it back in. When you plug it back in, allow it to regain sync before
    connecting any new equipment to it.

    The log except you showed indicates that the PIX isn't communicating
    past the modem, and is refusing the address that the modem, not the
    network, is trying to assign to it.

    --
    Warren H.

    ==========
    Disclaimer: My views reflect those of myself, and not my
    employer, my friends, nor (as she often tells me) my wife.
    Any resemblance to the views of anybody living or dead is
    coincidental. No animals were hurt in the writing of this
    response -- unless you count my dog who desperately wants
    to go outside now.
    Compare the newest tax preparation software apps:
    http://www.holzemville.com/mall/taxes/index.html
     
    Warren, Jan 25, 2005
    #4
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