Sonicwall TZ170 firewall not handing out DHCP leases

Posted on 2006-04-05
Last Modified: 2008-02-01
We are setting up a new office.  We have a T1 connected to a Cisco 2811 router then to a Sonicwall Tz170 firewall with enhanced OS.  The firewall, connectivity, etc all work fine.  The DHCP server is enabled (not passthrough) and a lease range of has been added w/ a subnet mask of  (we are using a class B for organizational purposes, not for sheer # of nodes).

When the PCs are set to static IPs in this range or any other, they work fine - LAN / internet access, etc all OK.  I can even get to the web management console on the FW.  But when set to DHCP, they are not able to aquire an IP address.  

I've contacted Sonicwall support but have not heard back yet.  Help!

Question by:cef_soothsayer
    LVL 3

    Expert Comment

    Do you have the DHCP set up on the right interface?  You can set up (or not) on both the lan and the opt interface.
    LVL 2

    Expert Comment

    run an ipconfig/all and see if you have another computer acting as a dhcp server handing out bad ip ranges
    LVL 1

    Author Comment

    FIXED - The problem was not the firewall at all.  The Cisco Catalyst Express 500 24TT swithc that it was plugged into was blocking DHCP relay request broadcasts.  This switch has "port roles" assigned to it and the role needed to be switched to "other".  The settings for "PC" or "Server" on this port were not working.

    Accepted Solution

    PAQed with points refunded (250)

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