Routers/Static Routes

Answered Question
Jan 29th, 2012

So heres my question.  Im running GNS3 with multiple routers, and a cloud to bring the internet in via the host pc.  I attached a screen shot of my Topology in GNS3 to give a visual of the setup.  I can ping out/telnet in via the internet to the first attached router (R4 in the topology), however none of my other routers can get out.  Im running EIGRP on all routers except R7, and all routes are discovered ok.  R4 has a route of last resort to the gateway (10.26.7.1).  I can ping all of the networks, I just cant ping out to the internet.  From any router except R4, I can  ping up to 10.26.7.3, but not the gateway of 10.26.7.1.  Im trying to figure out what Im missing here.  Can anyone shed some light?

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Correct Answer by Calin Chiorean about 2 years 2 months ago

Yes, you need one or more route back on 10.26.7.1

If you add static routes, then the next hop has to be your R4, 10.26.7.3

You need to add static routes for all networks that you have in your GNS3 "cloud".

Or establish a dynamic routing protocol between R4 and your L3 switch and push the networks to L3 switch through that dynamic routing protocol.

Let me know if this works!

Calin

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edondurguti Sun, 01/29/2012 - 21:44

Possibly you need to run nat in order to do that or redistribute ur gateway via R4 on eigrp or use the command default-network

I will try this tomorrow and let u know

Sent from Cisco Technical Support iPhone App

cdegroat82 Sun, 01/29/2012 - 22:01

I thought about NAT, and thought maybe its a GNS3 bug - however, I put an extra router on the network (R7).  I can ping the IP 192.168.1.1 from R1, but cant from anywhere else.  I feel like im missing some sort of static route, but I've tried a few, none seem to work.

Cadet Alain Sun, 01/29/2012 - 23:57

Hi,

did you try pinging 10.26.7.1 when the firewall on your host is disabled ?

for internet connectivity, first nat everything on R4 to the interface linking to your host NIC and tell us if you've got still the problem in which case tell us how you connect to the internet. posting your GNS3 net file would be great also.

Regards.

Alain

cdegroat82 Mon, 01/30/2012 - 10:52

Theres no firewall on 10.26.7.1, this is the IP of my L3 Switch.  Again, regardless of that, I have the same issue with R1 and R7.  R1 can ping to the 192.168.1.1 provided I have a static route set for it.  However, none of the other routers can hit that IP.  They can ping 16.1.1.1, but dont know how to get to R7.

Calin Chiorean Mon, 01/30/2012 - 00:51

Hello Chris,

I assume that on the box with 10.26.7.1 you have multiple interfaces. If this is a linux box,did you enable the packet forwarding between the interfaces?

cat /proc/sys/net/ipv4/ip_forward

If the result is 1 then your OK.

HTH,

Calin

cdegroat82 Mon, 01/30/2012 - 10:57

10.26.7.1 is not a Linux box or firewall, it is my Cisco L3 switch.

Calin Chiorean Mon, 01/30/2012 - 11:03

I see there a "cloud" next to 10.26.7.1 and I thought that the is physical interface where the interface cisco router interface is bounded to.

cdegroat82 Mon, 01/30/2012 - 11:07

It is the physical of my windows pc which is on that same subnet.  Firewall on or off doesnt matter.

Calin Chiorean Mon, 01/30/2012 - 11:15

OK, so let me see if I understand:

R4 (10.26.7.3) is logically bounded to your physical NIC, which is connected to a physical L3 switch with the IP address 10.26.7.1 (how is this configured? SVI or L3 port on switch).

Am I correct?

cdegroat82 Mon, 01/30/2012 - 11:31

Sort of.  R4s interface f0/0 IP  is bound to 10.26.7.3/24.  My PC NIC has 10.26.7.30/24 (via DHCP) and the L3 switch IP is 10.26.7.1/24.  R4 can communicate without issue to the internet/my other LANs just fine.  Its the other routers who cant route out, let alone ping 10.26.7.1.

Calin Chiorean Mon, 01/30/2012 - 11:41

Just a dump question, but do you push the default-route from R4 to the rest of the routers? Can you show an output of the routing table on another router (e.g. R2)?

cdegroat82 Mon, 01/30/2012 - 12:20

Now it sounds like what I was thinking.  How would I push that default route out?  Below is the routing table from R2.

Gateway of last resort is not set

     10.0.0.0/24 is subnetted, 1 subnets

D       10.26.7.0 [90/284160] via 12.1.1.2, 00:03:08, Ethernet1/1

     11.0.0.0/30 is subnetted, 1 subnets

C       11.1.1.0 is directly connected, Ethernet1/0

     12.0.0.0/30 is subnetted, 1 subnets

C       12.1.1.0 is directly connected, Ethernet1/1

     13.0.0.0/30 is subnetted, 1 subnets

D       13.1.1.0 [90/307200] via 15.1.1.5, 00:03:08, Ethernet1/2

                 [90/307200] via 12.1.1.2, 00:03:08, Ethernet1/1

     14.0.0.0/30 is subnetted, 1 subnets

D       14.1.1.0 [90/307200] via 15.1.1.5, 00:03:08, Ethernet1/2

                 [90/307200] via 11.1.1.1, 00:03:08, Ethernet1/0

     15.0.0.0/30 is subnetted, 2 subnets

C       15.1.1.4 is directly connected, Ethernet1/2

D       15.1.1.0 [90/307200] via 12.1.1.2, 00:03:08, Ethernet1/1

                 [90/307200] via 11.1.1.1, 00:03:08, Ethernet1/0

Calin Chiorean Mon, 01/30/2012 - 12:27

On R4:

ip route 0.0.0.0 0.0.0.0 x.x.x.x (next hop to the internet, yours is 10.26.7.1 if I understood correct)) 
! 
router eigrp xxx 
 redistribute static 
 default-metric 10000 1 255 1 1500

default-metric can be changed to whatever you need.

This is just a simple example to see if it's working.

Then check on R2 if you have a default route.

HTH,

Calin

cdegroat82 Mon, 01/30/2012 - 12:53

So this looks promising....The routing table on R2 is below.  I still cant ping 10.26.7.1 though.  Im wondering if I need routes back in to the GNS3 network on the L3 switch now....

Gateway of last resort is 12.1.1.2 to network 0.0.0.0

     10.0.0.0/24 is subnetted, 1 subnets

D       10.26.7.0 [90/284160] via 12.1.1.2, 00:34:32, Ethernet1/1

     11.0.0.0/30 is subnetted, 1 subnets

C       11.1.1.0 is directly connected, Ethernet1/0

     12.0.0.0/30 is subnetted, 1 subnets

C       12.1.1.0 is directly connected, Ethernet1/1

     13.0.0.0/30 is subnetted, 1 subnets

D       13.1.1.0 [90/307200] via 15.1.1.5, 00:34:32, Ethernet1/2

                 [90/307200] via 12.1.1.2, 00:34:32, Ethernet1/1

     14.0.0.0/30 is subnetted, 1 subnets

D       14.1.1.0 [90/307200] via 15.1.1.5, 00:34:32, Ethernet1/2

                 [90/307200] via 11.1.1.1, 00:34:32, Ethernet1/0

     15.0.0.0/30 is subnetted, 2 subnets

C       15.1.1.4 is directly connected, Ethernet1/2

D       15.1.1.0 [90/307200] via 12.1.1.2, 00:34:32, Ethernet1/1

                 [90/307200] via 11.1.1.1, 00:34:32, Ethernet1/0

D*EX 0.0.0.0/0 [170/281856] via 12.1.1.2, 00:00:20, Ethernet1/1

Correct Answer
Calin Chiorean Mon, 01/30/2012 - 13:02

Yes, you need one or more route back on 10.26.7.1

If you add static routes, then the next hop has to be your R4, 10.26.7.3

You need to add static routes for all networks that you have in your GNS3 "cloud".

Or establish a dynamic routing protocol between R4 and your L3 switch and push the networks to L3 switch through that dynamic routing protocol.

Let me know if this works!

Calin

cdegroat82 Mon, 01/30/2012 - 17:05

Calin - thank you!  This is exactly what was needed.  The main thing was not realizing how to push the static route out to the other routes.  Once I added the static routes back for all the subnets in GNS3, I was able to ping 10.26.7.1.  Then I just needed to do the same on my FiOS router - and I was able to route out to the internet!  Thanks again!

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Posted January 29, 2012 at 8:54 PM
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