ASA 5505 Transparent Mode

[network_guy]

Hello Everyone,

I just have 1 question. I am going to be getting UVerse installed at my house and have been having a hard time finding this in the documentation. The modem I am going to be getting is the 3800HGV-B. Over on the ATT forum users are stating that the modem needs every MAC of every potential IP. I thought about using it's DMZPlus mode but I am getting a block of 8 IP's and it doesn't seem to play nice unless it see's 5 different MAC's. Right now I have my 5505 in routed mode so I don't believe it passes the MAC of the client's through. Will the ASA pass the MAC of the client's through to the modem with the appropriate ACL's applied? Thanks for your help, I have looked at close to 200 pages tonight.

[varrao · Accepted solution]

Hi Joshua,

You can very well use the ASA in a transparent mode, the firewall would act as a L2 device and would  not proxy arp for the packets, which means the mac address of the host would be passed as is through the ASA.

Hope that helps.

Thanks,
Varun Rao
Security Team,
Cisco TAC

[network_guy]

Thanks Varun for your quick reply. I will be trying this tomorrow as that is my install date. Will get back with you if I have further questions. Thanks again.