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Cisco IOS Subnetting

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Gamingphreek

Lifer
Mar 31, 2003
11,679
0
81
Yes, because the WAN side of all the routers are on the same network. Networks that are directly connected to an interface are automatically put in the routing table. The LAN side of Site A will not be in the routing table of the C router, unless configured or a routing protocol is configured.

OH - I completely understand. I'll post it first thing tomorrow.

-GP
 

Gamingphreek

Lifer
Mar 31, 2003
11,679
0
81
Here are the routing tables for the other 2 sites:

Site C:
Code:
Gateway of last resort is 10.1.2.10 to network 0.0.0.0

10.1.0.0/30 is subnetted, 1 subnets
C   10.1.2.8 is directly connected, FastEthernet0/0
192.168.0.0/27 is subnetted, 1 subnets
C   192.168.0.64 is directly connected, Fast Ethernet0/1
S* 0.0.0.0/0 [1/0] via 10.1.2.10

Site B:
Code:
Gateway of last resort is 10.1.2.5 to network 0.0.0.0

10.1.0.0/30 is subnetted, 1 subnets
C   10.1.2.4 is directly connected, FastEthernet0/0
192.168.0.0/27 is subnetted, 1 subnets
C   192.168.0.32 is directly connected, Fast Ethernet0/1
S* 0.0.0.0/0 [1/0] via 10.1.2.5

That should be everything.

-GP
 

her209

No Lifer
Oct 11, 2000
56,336
11
0
OK, based on you routing tables and the network diagram you've posted, there are couple weird things:

Code:
Gateway of last resort is 10.1.2.2 to network 0.0.0.0
   10.1.0.0/30 is subnetted, 2 subnets
C   10.1.1.0 is directly connected FastEthernet0/0
C   10.1.2.0 is directly connected FastEthernet0/1
   192.0.0.0/27 is subnetted, 1 subnet
S   192.168.0.0[1/0] via 10.1.2.0
S* 0.0.0.0/0[1/0] via 10.1.1.0

Site C:
Code:
Gateway of last resort is 10.1.2.10 to network 0.0.0.0

10.1.0.0/30 is subnetted, 1 subnets
C   10.1.2.8 is directly connected, FastEthernet0/0
192.168.0.0/27 is subnetted, 1 subnets
C   192.168.0.64 is directly connected, Fast Ethernet0/1
S* 0.0.0.0/0 [1/0] via 10.1.2.10

Site B:
Code:
Gateway of last resort is 10.1.2.5 to network 0.0.0.0

10.1.0.0/30 is subnetted, 1 subnets
C   10.1.2.4 is directly connected, FastEthernet0/0
192.168.0.0/27 is subnetted, 1 subnets
C   192.168.0.32 is directly connected, Fast Ethernet0/1
S* 0.0.0.0/0 [1/0] via 10.1.2.5

I imposed the network address onto your network diagram:

Network_Diagram.jpg


- Why are the WAN-facing interfaces in different subnets (10.1.2.0/30, 10.1.2.4/30, 10.1.2.8/30)?
- The router at Site C has interfaces with /30 subnets (10.1.1.0/30, 10.1.2.0/30). Does that mean the network behind the ASA firewall is another completely different network?
 

Gamingphreek

Lifer
Mar 31, 2003
11,679
0
81
First off - awesome graphic. That is exactly how the network is set up - thanks so much for taking the time to help.

- Why are the WAN-facing interfaces in different subnets (10.1.2.0/30, 10.1.2.4/30, 10.1.2.8/30)?

To be honest, I don't know. I can say that each site has its own subnet.

So Sites A, B and C each have one address for the Network, the VPN hub, the Router, and Broadcast. Why they aren't all on the same network... not sure. They shouldn't have to be, correct?

- The router at Site C has interfaces with /30 subnets (10.1.1.0/30, 10.1.2.0/30). Does that mean the network behind the ASA firewall is another completely different network?

This is to separate my servers and equipment from the remote sites. Not a completely different network, just a way to separate things (ie: I should have 1 address for Network, Router, ASA, Broadcast)

-GP
 

MtnMan

Diamond Member
Jul 27, 2004
9,418
8,815
136
- Why are the WAN-facing interfaces in different subnets (10.1.2.0/30, 10.1.2.4/30, 10.1.2.8/30)?

To be honest, I don't know. I can say that each site has its own subnet.
Devices on different subnets cannot directly communicate with each other, there would have to be a layer 3 device in there somewhere.

This leads to the question, what is the cloud in the WAN network?
 

Gamingphreek

Lifer
Mar 31, 2003
11,679
0
81
Devices on different subnets cannot directly communicate with each other, there would have to be a layer 3 device in there somewhere.

This leads to the question, what is the cloud in the WAN network?

The giant cloud in between all of the sites is the internet.
 

MtnMan

Diamond Member
Jul 27, 2004
9,418
8,815
136
Are you using NAT, i.e. do you have private IPs on your sites, and using NAT to the public assigned by your ISP?
 

alkemyst

No Lifer
Feb 13, 2001
83,769
19
81
Anyone have any ideas? I'm out of ideas to be honest...

Put the WAN facing interfaces into the same subnet and let the routers then route to the internal network.

you can use a /29 address space (10.1.2.0->10.1.2.7).

The problem is going to be though that private IP addresses don't mean anything once they hit the WAN. Those links will have to be setup across your WAN provider or you can get public IP space for them. So you'd need a /29 public IP space for the three sites (and you'd be able to grow to 6 sites in total. That'd be the easiest way.

Also if those devices have WAN interfaces that get a public IP address you can put those into your routing table statically.