Anybody help me figure this one out - problem pinging! [Archive]

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denzel564

12-11-2010, 08:07 AM

Hi Guys,

I'm pretty sure there's someone who can help me figure this one out.

I cant ping successfully across a network from a lab I built using packet tracer. I can ping from within each subnet .i.e host to gateway and for serial int to serial int, but not from router- router or host-router across different subnets. ( I know what I'm missing must be quite simple )

Pls note:

RIP = routing protocol.

networks: 172.16.10.0
172.16.20.0
172.16.30.0
172.16.40.0
172.16.50.0

Lab is on page 656 and 657 of the access list chapter of CCNA study guide..todd Lammle. ( I've attached my config for those who have packet tracer to see where I'm going wrong - had to zip it so i could upload as uploader doesnt accept *.pkt files)

Any one out there !!! ?? :pthanks in advance

DonB

12-11-2010, 08:14 PM

Can you post your confgs directly (text) or in std format like jpep or gif? I do not have packet tracer.

Thanks

denzel564

12-13-2010, 07:35 AM

Looking forward to your reply! many thanks:cool:

Fuzz

12-13-2010, 09:23 AM

Set your default gateways on the hosts.

denzel564

12-13-2010, 09:56 AM

Set your default gateways on the hosts.
Thanks for the reply. I added the default gateways to the hosts. No joy. Any other suggestions. ?:rolleyes::D

DonB

12-13-2010, 01:16 PM

The main problem is that you are using rip v1. Ripv1 is classfull. You cannot use 172.16.0.0 across all routers using ripv1. You need to use a routing protocol that allows the use of subnets such as ripv2,ospf, eigrp

Fuzz

12-14-2010, 02:27 AM

Thanks for the reply. I added the default gateways to the hosts. No joy. Any other suggestions. ?:rolleyes::D

I don't know, because when I opened your pkt file in my PT and added the default gateway to a couple of hosts, I could ping from those hosts across all network devices.....

The main problem is that you are using rip v1. Ripv1 is classfull. You cannot use 172.16.0.0 across all routers using ripv1

You can if you use the same mask length on all devices.

denzel564

12-14-2010, 03:57 AM

HermeszData

12-14-2010, 09:30 AM

Hey all.

Once again thanks for trying to figure this out. I have changed to eigrp and verfied using 'show ip route' and all routes show up. But once again, I can only ping from hosts to default gateways and from Routers to Routers ( Router A to router C and vice versa, but cannot ping to a different subnet.

Fuzz, my subnet masks are all /24.

This is a strange one...common there must be a waaaaaaaaaaay:confused::D

Fuzz, you say you were able to do it. ? How though?

What does the routing table look like?

sh ip route

This will at least let you know if your routing table is populating properly.
also sh ip int br to make sure all interfaces are up/up

The last thing is to confirm that RouterB's serial interfaces are connected to the proper adjacent router. This is not clear from the PT image. Begause you indcated that eigrp does not route for you your physical interconnect would be my first suspect!

denzel564

12-14-2010, 11:03 AM

Routing tables for the 3 routers as follows:

routerA>
routerA>
routerA>en
routerA#sh ip route
Codes: C - connected, S - static, I - IGRP, 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, E - EGP
i - IS-IS, 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 not set
172.16.0.0/24 is subnetted, 5 subnets
C 172.16.10.0 is directly connected, FastEthernet0/0
C 172.16.20.0 is directly connected, Serial2/0
D 172.16.30.0 [90/20514560] via 172.16.20.254, 00:00:18, Serial2/0
D 172.16.40.0 [90/21024000] via 172.16.20.254, 00:00:18, Serial2/0
D 172.16.50.0 [90/21026560] via 172.16.20.254, 00:00:17, Serial2/0

__________________________________________________ ______________

routerB>
routerB>
routerB>en
routerB#sh ip route
Codes: C - connected, S - static, I - IGRP, 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, E - EGP
i - IS-IS, 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 not set
172.16.0.0/24 is subnetted, 5 subnets
D 172.16.10.0 [90/20514560] via 172.16.20.1, 00:01:18, Serial2/0
C 172.16.20.0 is directly connected, Serial2/0
C 172.16.30.0 is directly connected, FastEthernet0/0
C 172.16.40.0 is directly connected, Serial3/0
D 172.16.50.0 [90/20514560] via 172.16.40.254, 00:01:18, Serial3/0

__________________________________________________ ___

routerC>
routerC>en
routerC#sh ip route
Codes: C - connected, S - static, I - IGRP, 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, E - EGP
i - IS-IS, 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 not set
172.16.0.0/24 is subnetted, 5 subnets
D 172.16.10.0 [90/21026560] via 172.16.40.1, 00:01:54, Serial2/0
D 172.16.20.0 [90/21024000] via 172.16.40.1, 00:01:54, Serial2/0
D 172.16.30.0 [90/20514560] via 172.16.40.1, 00:01:54, Serial2/0
C 172.16.40.0 is directly connected, Serial2/0
C 172.16.50.0 is directly connected, FastEthernet0/0

HermeszData

12-14-2010, 02:15 PM

Based on the information above, you should be able to ping any device/host on the network from any other device. All three routers have all the routes to all networks in the network diagram.

From your original post:

I can ping from within each subnet .i.e host to gateway and for serial int to serial int, but not from router- router or host-router across different subnets.

This problem indicates a Host NIC configuration issue. If you are unable to ping the serial interface on the router that a host is connected to, it is because the host does not know where to find that interface.

On the Host NIC config:
IP Address - 172.17.{subnet for the routers LAN}.{host IP Address}
Subnet Mask - 255.255.255.0 - because you are using \24 mask
Gateway - 172.17.{subnet for the routers LAN}.1 - per the configs previously attached in .txt file.

I have run these configs on actual hardware in my lab I (don't use PT) an I no problems pinging devices attached to the different networks.

Not that it is an issue, but I would remove the application of the access list on RouterA F0/0 until you first have confirmed end-to-end connectivity within the network as described.

John

denzel564

12-15-2010, 04:53 AM

HermeszData

12-24-2010, 01:34 PM

Thanks John and everyone else who helped me solve this.¬!

John, your advice to remove access list from fa0/0 and see if this solves the problem has fixed issue.

I can now ping across the network now!

Simple lesson learnt: Do not add other configs till network connectivity has been checked. I knew this, but was too eager to setup access lists:)

You guys are very helpful! I'll be back again if i have any other issues!!

The access list should have allowed you to ping PC1 only from PC2. It should not have prevented any communication between PCs 2,3,4,5.

Sounds like you skipped a couple of Troubleshooting 101 steps. "Been there done that! Have the headaches to show for it!"

Can I ping -> PC1 to PC2,3,4,5? PC2 YES! PC3,4,5 NO! (based on the ACL)
Can I ping -> PC2 to PC1,3,4,5? YES! (At least you you should be able to based on the ACL)
Can I ping -> PC3 to PC1,2,4,5? YES, except PC1 (see above)
Can I ping -> PC4 to PC1,2,4,5? YES, except PC1 (see above)
Can I ping -> PC45 to PC1,2,3,4? YES, except PC1 (see above)

With no ACLs set on Routers B and C, you should have been able to ping between the hosts connected to routers B and C. Pings sent from PC1 would reach their destinations but ICMP replies from PC3,4,5 would be blocked by the ACL on RouterA.

This is how we learn!

Glad I was able to help.