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DHCPD Problems with 6.3(4) on a PIX 501

Level 1
Level 1


I have a PIX 501 that is configured as a DHCP server for some internal hosts consisting of Thin Clients (Neoware and Wyse) and PC's.

For the last few weeks, the DHCP service has been acting up and refusing to assign addresses to the Thin Client workstations.

I ran a capture on the Inside interface to log DHCP requests from the clients. It shows that the requests were sent to the broadcast, but the PIX doesn't send any responses back. In a 'show dhcpd stat', it shows that there are 16 expired bindings, which I suspect is the cause. However, I can't clean out the expired bindings and I assume the PIX is ignoring the requests because they are for new addresses and not for renewals.

To only way I've been able to correct the problem (temporarily) is to either reboot the PIX, or do a 'clear dhcpd' and re-enter the configuration.

Listed below is my current DHCPD configuration and attached is the output of a show capture.

In the capture, the DHCPD configuration was reset at 16:13:35. You can see that DHCP requests are now being answered to some of the addresses that were previously ignored. The PC's were always able to renew addresses properly.

Has anyone run into this problem and found a proper resolution for it?

dhcpd address inside

dhcpd dns yyy.yyy.yyy.yyy

dhcpd lease 1800

dhcpd ping_timeout 750

dhcpd domain office.intranet

dhcpd enable inside


2 Replies 2

Level 1
Level 1

Hi Joshua,

Didn't a PIX 501 only supported 32 DHCPD clients?

Kind regards Eric

I thought I responded to this awhile ago, but I guess I never clicked on submit...

The PIX in question is licensed for 50 users. When using DHCPD on a 50 user PIX 501, the DHCP server supports up to 128 leases.

Good guess, but that's not what the problem is :-)


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