Tech Support > Computer Hardware > Routers > Obtain DNS Information from Provider
Obtain DNS Information from Provider
Posted by DCS on April 26th, 2006


I have an 1800 ISR router with an ADSL HWIC. The HWIC is configured
and I'm connecting to the provider without any problems. Behind that,
I have an ASA firewall coming from an internal interface on the ISR. I
have been using the DNS settings provided by my ISP to manually
conifgure my client stations on the inside of the ASA and would like to
transition to DHCP.

When using the ISPs DSL modem, the modem obtains the DNS information
for that session which periodically changes. How can I configure my
1800 ISR to get this DNS information, pass it to my ASA, and have the
ASA use this information when leasing IPs to clients?

Thanks~! DCS

Posted by Merv on April 27th, 2006


assuming 1800 is getting its IP and DSN info via DHCP, then set up a
DHCP pool on the 1800 configured with the import all function.

On the ASA configure DHCP relay to relay DHCP client requests from PCs
thru the ASA to the 1800

Posted by DCS on April 27th, 2006


Hey,

The IPs are static but the ISP DNS servers, while MOSTLY static do
change occassionally. The gateways the ISPs use seem to be able to get
this information during their negotiation and I'd like like to replace
their gateway and have all that information negotiated with my router.

Merv wrote:

Posted by Merv on April 27th, 2006


Can you please provide an ASCII diagram of the current setup and the
planned setup

When you say ISP gateway exactly what are you referring to ?

Is it a device at your site ?