Cisco – internet access to remote subnet

cisconat;

I have a main building with static NAT (One IP Address from ISP) and a remote building with a Point to Point T1 connecting it to the main building.

If I use eigrp and redistribute static I can access both subnets but do not gain internet access from the branch building. I have tested several different eigrp and static routing configs with no success.

main building:
router eigrp 1
network 10.1.1.0 0.0.0.3
network 10.10.16.0 0.0.0.255
redistribute static metric 1544 2000 255 1 1500

branch building:
router eigrp 1
network 10.1.1.0 0.0.0.3
network 10.10.17.0 0.0.0.255

The attached diagram shows my current conifg to allow all subnets to use the one isp internet connection. But doing double nat isn't best solution.

enter image description here

Best Answer

Regarding NAT: I get that you are fixing the problem with your NAT by NAT-ing everything from the branch point-to-point subnet so the interfaced is marked for NAT at HQ. But i would remove that and create a static NAT on HQ for the branch office network, so that traffic get's NAT-ted as well.

Regarding EIGRP: Please make sure you have no auto-summary on eigrp peers. From the discussion and the info we have nothing seems the matter with the EIGRP config. However have a look at if you by accident don't have a static default route on your branch router. Make sure your branch router has IP Classless enabled, this makes sure that if a packet is received which does not have a more specific route it will choose the default route. Check your routing table and eigrp topology table to see if you see the route. You can also do debug eigrp to see if you see any relevant updates.

If all else fails try clear your adjacency to make sure that the tables aren't stuck. To make sure you can double check by creating as static route point to HQ router since it's such a small setup, and not that dynamic ?

There is also other methods for redistributing, though the method you chose is the most common one.

  1. Create a static route and redistribute (you can have metric or skip it for default metrics)
  2. Create a ip summary address to default route towards the branch
  3. ip default-network (BAD)
  4. network 0.0.0.0 command under eigrp (BAD)

EDIT: The NAT

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