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lejeune franck

lejeunefranck
Level 1
Level 1

Why R1 can go on internet but not R2 ?

R1 and R2 created adjacency with OSPF. can ping each other. 

R1 can ping 8.8.8.8 but R2 can t.

1 Accepted Solution

Accepted Solutions

We still have minimal information on R2 - that's where the routing table is "needed" for diagnostics.

Presumably the NAT function is done on the Verizon cable router.  IT presumably knows the way back to 192.168.1.x addresses, but no other - and it will NOT know how to get back to 192.168.3.0.  Even if you ping 192.168.1.1 from R2, you won't get a response ?  This is because the packet makes it TO the verizon router; but it doesn't know how/where to return the packet to anything internal other than 192.168.1.x, unless it has additional static routes in place to get the packet back to R1 (who DOES know how to get to 192.168.3.x addresses).

So, you'll either have to modify the verizon to get that to work; or to NAT on R1's interface to R2 that they look (to Verizon) like they are coming from additional 192.168.1.x ports using one of the NAT / PAT schemes.

View solution in original post

5 Replies 5

pwwiddicombe
Level 4
Level 4

Minimal information here.  Config listing from R1 and R2 would help.

However, on R2, what all do you see on "sh ip ro" ?  Do you have all the routes you should see from R1; and do you have a default route from R2 to R1 ?

Hi,

Im currently trying to access internet with a cisco lab and a verizon router, but Its look like i'm missing something.

Will try to be clear in my description of the network.

 

Hardware  : 2 routers cisco 1760. R1 and R2 link together via serial 0/0.(10.1.1.0 /30) (wic card t1) and a cable verizon router quantum g1100.

 

-verizon cable router(192.168.1.1)  is connected with  R1 FA0/0 192.168.1.200 

-on R1 i added  IP route 0.0.0.0 0.0.0.0 192.168.1.1 

-from R1 I can ping google 8.8.8.8.

 

The problem occur when i try to ping the verizon router (192.168.1.1) from R2 (connected thru serial 0/0 with R1).

-from R2 i can ping the address 192.168.1.200 (R1 FA0/0) but can't reach the verizon router. 

 

its looks like im block at R1 FA0/0.  

 

OSPF is running on both R1 and R2. 

 

Here is the copy of the routing table on R1

 

Sending 5, 100-byte ICMP Echos to 8.8.8.8, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 12/14/16 ms

R1#sh ip route

Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP

       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area 

       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

       E1 - OSPF external type 1, E2 - OSPF external type 2

       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2

       ia - IS-IS inter area, * - candidate default, U - per-user static route

       o - ODR, P - periodic downloaded static route

 

Gateway of last resort is 192.168.1.1 to network 0.0.0.0

 

     1.0.0.0/32 is subnetted, 1 subnets

C       1.1.1.1 is directly connected, Loopback0

     2.0.0.0/32 is subnetted, 1 subnets

O       2.2.2.2 [110/65] via 10.1.1.2, 00:10:23, Serial0/0

     10.0.0.0/30 is subnetted, 1 subnets

C       10.1.1.0 is directly connected, Serial0/0

C    192.168.1.0/24 is directly connected, FastEthernet0/0

S    192.168.3.0/24 [1/0] via 10.1.1.2

S*   0.0.0.0/0 [1/0] via 192.168.1.1

 

We still have minimal information on R2 - that's where the routing table is "needed" for diagnostics.

Presumably the NAT function is done on the Verizon cable router.  IT presumably knows the way back to 192.168.1.x addresses, but no other - and it will NOT know how to get back to 192.168.3.0.  Even if you ping 192.168.1.1 from R2, you won't get a response ?  This is because the packet makes it TO the verizon router; but it doesn't know how/where to return the packet to anything internal other than 192.168.1.x, unless it has additional static routes in place to get the packet back to R1 (who DOES know how to get to 192.168.3.x addresses).

So, you'll either have to modify the verizon to get that to work; or to NAT on R1's interface to R2 that they look (to Verizon) like they are coming from additional 192.168.1.x ports using one of the NAT / PAT schemes.

Thanks for your help

Here his both ip route table for R1 and R2.

will try the NAT/PAT shemes on R1.

R1#ping 8.8.8.8

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 8.8.8.8, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 12/13/16 ms
R1#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route

Gateway of last resort is 192.168.1.1 to network 0.0.0.0

1.0.0.0/32 is subnetted, 1 subnets
C 1.1.1.1 is directly connected, Loopback0
2.0.0.0/32 is subnetted, 1 subnets
O 2.2.2.2 [110/65] via 10.1.1.2, 00:19:50, Serial0/0
3.0.0.0/32 is subnetted, 1 subnets
O 3.3.3.3 [110/129] via 10.1.1.2, 00:19:50, Serial0/0
10.0.0.0/30 is subnetted, 2 subnets
C 10.1.1.0 is directly connected, Serial0/0
O 10.1.1.4 [110/128] via 10.1.1.2, 00:19:50, Serial0/0
C* 192.168.1.0/24 is directly connected, FastEthernet0/0
S 192.168.3.0/24 is directly connected, Serial0/0
S* 0.0.0.0/0 [1/0] via 192.168.1.1

-------------------------------------------------------------------------------

R2#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route

Gateway of last resort is 10.1.1.1 to network 0.0.0.0

1.0.0.0/32 is subnetted, 1 subnets
O 1.1.1.1 [110/65] via 10.1.1.1, 00:22:11, Serial0/0
2.0.0.0/32 is subnetted, 1 subnets
C 2.2.2.2 is directly connected, Loopback0
3.0.0.0/32 is subnetted, 1 subnets
O 3.3.3.3 [110/65] via 10.1.1.6, 00:22:11, Serial1/0
10.0.0.0/30 is subnetted, 2 subnets
C 10.1.1.0 is directly connected, Serial0/0
C 10.1.1.4 is directly connected, Serial1/0
O 192.168.1.0/24 [110/65] via 10.1.1.1, 00:11:33, Serial0/0
C 192.168.3.0/24 is directly connected, FastEthernet0/0
O*E2 0.0.0.0/0 [110/1] via 10.1.1.1, 00:09:05, Serial0/0

thanks pwwiddicombe.

Your idea about NAT/PAT was good.

First i  add a static NAT on R1 for 192.168.3.0 to see and  I was able to ping google but i couldn't ping anymore from R1.

then with an access-list permit any on R1

R1(config)#access-list 1 permit any 

R1(config)#ip nat inside source list 1 int fa0/0 overload

its works fine from any networks. 

I guess with all the command i have tried and deleted the config is horrible and not  optimal but it made me understand some good things. 

thanks again.

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