ASA 5505 dropping DHCP assignments

Paul Ledbetter · ‎01-26-2015

I have a ASA 5505 set up as a DHCP server at a customer site. I have 3 clients connected to the inside interface. The outside interface is connected to my Comcast cable modem. Initially after firewall reload (reboot), all works as expected All three clients receive their IP addresses, and Internet access is fine. Then after varying amounts of time, (30 minutes to 4 hours or more) each client in turn loses connection to the Internet. An ipconfig on each client shows that it has lost its assigned address, and has reverted to its autoconfiguration address. Renewing the IP address, and disabling and reenabling the NIC does not help. It remains at its autoconfiguration address. Only a reload of the firewall corrects the problem, only to have the problem repeat itself, with no consistency on when it happens. There are no other devices connected to the firewall. When I set the clients to static IPs, the problem goes away.

Attached is my running config, sensitive entries stripped out

JORGE RODRIGUEZ · ‎08-23-2015

You have to either run a capture or debug dhcpd on the firewall to get some info as to why not getting the IPs from the firewall

capture

http://www.cisco.com/c/en/us/support/docs/security/asa-5500-x-series-next-generation-firewalls/116354-technote-asa-00.html

debug dhcpd <events>

http://www.cisco.com/c/en/us/td/docs/security/asa/asa82/command/reference/cmd_ref/d1.html#wp2034318

Jorge Rodriguez