Redundant WAN connection on Cisco 1811

[Logmaster]

Hi,

I am trying to configure a secondary internet connection. My primary connection is a AT&T DSL connection with a static IP (IP is static however negotiated) and static DNS servers. The secondary connection is a Comcast Cable connection. I have a few questions:
1.How can I configure the Comcast connection to either work with Dynamic/static DNS servers from Comcast? (Currently, it’s trying to use the ATT DNS servers)?

2.What is the best way to define connection redundancy? (Assign one line as primary for certain services and redirect to the other line if the line is down)

3. Is there a way to define DDNS that will use the IP address of the main line unless the line is down? If down, DDNS will use the secondary IP address?

4. Is there a way to define two DDNS for each one the connections that will do what’s the described in Paragraph 3?

5. Are there any recommended tutorials on those topics?

Regards,
Joe

 

[voltron1011]

You can do floating default routes with track statements, like this:

!
ip sla monitor 100
type echo protocol ipIcmpEcho 10.100.7.1 source-interface FastEthernet0/1
timeout 500
frequency 3
ip sla monitor schedule 100 life forever start-time now
!
!
!
interface FastEthernet0/0
description TestLAN
ip address 192.168.1.1 255.255.255.0
ip nat inside
ip virtual-reassembly
shutdown
duplex auto
speed auto
!
interface FastEthernet0/1
description ISP_A (Our corp. LAN to internet)
ip address 10.100.7.200 255.255.255.0
ip nat outside
ip virtual-reassembly
shutdown
duplex auto
speed auto
!
interface FastEthernet1/0
description ISP_B (COX cable DHCP)
ip address dhcp
ip nat outside
ip virtual-reassembly
shutdown
duplex auto
speed auto
!
!
!
ip route 0.0.0.0 0.0.0.0 FastEthernet0/1 10 name ISP_A track 100
ip route 0.0.0.0 0.0.0.0 24.234.xxx.xx 251 name ISP_B
!
ip nat inside source route-map ISP_A interface FastEthernet0/1 overload
ip nat inside source route-map ISP_B interface FastEthernet1/0 overload
!

 

[Logmaster]

Hi,

Thanks for the advice, how should I handle the different DNS servers for each one of the connections? Is there a way to define that the router will get DNS servers addresses when the IP address is negotiated?

Is there a way to dynamically define DDNS?

Thanks again,
Joe