Question:
Ping not working in packet tracert.. help?
TheAllKnowing
2011-03-09 07:22:23 UTC
ok.. so i have 3 routers but i'm only worrying about router 1 and 2 for now.. if i can get these too work then the third router will be easy.

http://img842.imageshack.us/i/55600295.jpg/ (picture of layout)

FastEthernet for Router 1 = 193.60.60.1/26 (255.255.255.192)
Serial Link from router 1 to router 2= 192.168.0.1/26 (255.255.255.192)

FastEthernet for Router 2 = 193.60.60.129/26 (255.255.255.192)
Serial Link from router 2 to router 1 = 192.168.0.2/26 (255.255.255.192)

I have ripped the routers as 192.168.0.0 and 193.60.60.0 on both of the routers but for some reason the ping from machines doesn't work... i have set a clock rate on the machines of 56000... if anyone can see why this doesnt work then please leave an answer as it will be very appreciated
Four answers:
Pablo
2011-03-09 19:51:01 UTC
* Explanation:



There is no communication between the LAN networks 193.60.60.0/26 (Router1) and 193.60.60.128/26 (Router2) because this internet hasn't converged and won't, as long as you keep using a classful routing protocol, which is RIPv1 in this case.



The key point to understand is that RIPv1 doesn't converge on discontiguous network topologies because it is a classful routing protocol, and thus it doesn't send the subnet masks as part of its routing updates. Here you have subnets 193.60.60.0/26 and 193.60.60.128/26 separated by network 192.168.0.0/26. This makes 193.60.60.x a discontiguous network.



If you take a look at the routing tables of both Router1 and Router2, you'll see neither of them shows that they can reach the remote 193.60.60.x/26 subnet via its neighbor router, so there is no communication beyond each local network, except reaching its own router's interfaces.



About your question in the Additional Details section, you see the "Destination Host Unreachable" ICMP message from Router2 because, as we just said in the previous paragraph, its routing table doesn't contain an entry (path) to reach the remote network 193.60.60.0/26. This is assuming you tried to ping the FastEthernet interface (193.60.60.1). Now, if you try to ping Router1's Serial interface, you'll only get a timeout as Router1 doesn't have a route back to the remote network (193.60.60.128/26) to send the ICMP echo reply message (the "ping answer").



* Possible solutions? Just choose one:



. . . 1. Use a classless routing protocol, such as RIPv2, EIGRP or OSPF, instead of the classful RIPv1.



. . . 2. If you still want to use RIPv1, then don't use discontiguous networks. In this case, keep both subnets 193.60.60.x connected to the same router and make sure you're still using the same subnet mask for both subnets.



. . . 3. While still keeping RIPv1, replace one of the two 193.60.60.x subnets with another major network (A, B, C) address. Just make sure you don't separate the subnets from the same router, that is, make sure you don't use discontiguous networks.



* Notes:

. . . @Harold, this topology is not affected by the use of Ethernet switches (unless certain specific configuration is made). A new out-of-the-box Cisco switch does its primary job very well without any initial configuration, and the same applies here if the asker just selected them from the selection box of Packet Tracer.
2011-03-09 09:22:40 UTC
I know why :) Because you have them hooked up to switches. If you haven't studied switches before (I assume you haven't since you're doing routers now and switches usually come after routers) you need to know some things. Switches need to be configured to do what you're trying to do (and the routers need more configuration). Take out the switches and you'll be able to ping. Hope that helps.



Edit: He is running 3 different subnets. He's using VLSM... he doesn't have to use classful addresses so his address scheme is fine. (though make sure you're running RIPv2)
izus
2011-03-09 07:49:49 UTC
im actually setting up 3 routers also right now.



first off its always easier if they are the same type of router.



and i would think you should be running 3 separate subnets class'.



location 1

192.168.0.0 with a subnet of 255.255.255.0



location 2

172.16.0.0 with a subnet of 255.255.0.0



location 3

10.0.0.0 w a subnet of 255.0.0.0
?
2016-12-13 14:21:19 UTC
nicely in my openio tracert request is going to ur DNS first, respond u from there. At DNS it reveals yet another community ip it is unquestionably greater point router, next ur request is transmitted from DNS server to the subsequent hop, from the place it particularly is going to additionally respond u. Then pass upward and upward etc...............


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