topic ASA DHCP Relay Issue in Network Security

ASA DHCP Relay Issue

friek — Mon, 11 Mar 2019 20:07:57 GMT

Hi,

I have been trying to get DHCP realy in a ASA runing 7.2(1) working with no luck. I added the following the commands to the ASA:

dhcprelay server x.x.x.x inside

dhcprelay enable wifi

So I'm trying to pass the dhcp requests from the wifi interface (security level 60) to the inside interface (security level 100). I can see the dhcp request on the dhcp server and a lease being issued. However it never reaches the device on the wifi interface. I have done data caputures and I see it on the inside interface (not on the same phyiscal segment as the ASA inside interface). When I have debug dhcp events I see a binding. When I sniff the wifi interface I can see the dhcp requests but ro replies.

All the examples show going from a higher security interface to a lower security interface. As anybody configured a ASA in this manor?

Any assistance will be greatly appreicated.

Re: ASA DHCP Relay Issue

PAUL GILBERT ARIAS — Wed, 16 Mar 2011 19:45:08 GMT

If the DHCP server is on the interface called wifi and the clients are on the inside you will need the following commands:

dhcprelay server x.x.x.x wifi

dhcprelay enable inside

check the following link:

http://www.cisco.com/en/US/partner/docs/security/asa/asa82/command/reference/d2.html#wp1949399

It show an example:

The following example shows how to configure the DHCP relay agent for a DHCP server with an IP address of 10.1.1.1 on the outside interface of the adaptive security appliance, client requests on the inside interface of the adaptive security appliance, and a timeout value up to 90 seconds:

hostname(config)# dhcprelay server 10.1.1.1 outside

hostname(config)# dhcprelay enable inside

I hope this helps.

Re: ASA DHCP Relay Issue

friek — Wed, 16 Mar 2011 20:37:36 GMT

Thank you but I have read that link....many many times.

As I indicated my DHCP server is behind the ASA on the inside interface (security level 100) and the clients are on the wifi interface (security level 60). My question is this, has anybody been able to get dhcprelay on a ASA to work with the dhcp request flow is from a lower level security interface to a higher level security interface.

Is there more to the configuration then simply dhcprelay server x.x.x.x inside and dhcprelay enable wifi..........

Re: ASA DHCP Relay Issue

PAUL GILBERT ARIAS — Wed, 16 Mar 2011 20:42:11 GMT

I thought your dhcp server was on the interface wifi, sorry for the error.

I have done DHCP relay and it works. You can also try to troublehoot the problem checking the logs and/or debugs.

The DHCP server is on the same subnet as the interface inside? Same question for the DHCP clients

ASA DHCP Relay Issue

smailbouabdallah — Fri, 05 Aug 2011 14:18:04 GMT

Hi,

anyone has a configuration for this issue or how it setup?