Hi kyleobrogers,,Check this document which contain the changes you need to apply on your 5555-X configuration, let me know if you need further help.http://www.cisco.com/c/en/us/products/collateral/security/asa-5500-series-next-generation-firewalls/gu...

Hi hencar,, try to upgrade your firmware version to the release 3.5.29.2. let me know if you already have this version installed in your modem.

Hi Zavira,, check this web site where you can see an example that is similar to your case.http://www.cisco.com/c/en/us/td/docs/ios/12_2/12_2b/12_2b4/feature/guide/12b_dhc.html