Cisco ASA 5520 and DHCP relay

Simon Hobson dhcp1 at
Fri Mar 14 11:29:04 UTC 2008

Eimantas Zdaneviãius wrote:

>I find configuration error in asa acl. There was 
>no accept rule for
>And now linux gets its ip address. I cant belive 
>that windows gets its ip addres when there was 
>no accept rule in asa.

Are you certain it did ? A few things come to mind :

1) I don't know if this is a new network setup, 
or a replacement router. If Windows already had 
an unexpired lease, then it could be using that.

2) Again, if Windows already had a lease, it 
could be using unicast to renew it (so not 
reliant on the relay agent).

3) Again, if it had an existing lease, it might 
not be using the broadcast address.

4) At some point you didn't have the access list 
in place, so that allowed Windows to get a lease.

>Only one thing now is that i cant resolve domain names into ip.
>if i type 'ping', my laptop try 
>to resolve ''.
>Where i need to search for misconfiguration: 
>dhcp server, dhcprelay or dhcp client?

Windows or Linux client ?

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