Using extended ping command

[Jeremy Dubrulle]

Hi, I'm trying to use the extended ping command on a Cisco 3750 switch but I don't understand the IP Header options.

I'd like to specify the next-hop of the packet, and if I can, specify also the next-hop of the next-hop, etc.

As I see in the cisco doc :

• Verbose is automatically selected along with any other option.
• Record is a very useful option because it displays the address(es) of the hops (up to nine) the packet goes through.
• Loose allows you to influence the path by specifying the address(es) of the hop(s) you want the packet to go through.
• Strict is used to specify the hop(s) that you want the packet to go through, but no other hop(s) are allowed to be visited.

But when I select Loose or Strict, I have to enter a "source route", that's all. And when I give the next-hop as the source route, obviously it doesn't work.

[Joseph W. Doherty]

"source route" means you need to enter the list of hops, in sequence, you want the packet to take. ("Source route" means the source is selecting how to route the packet rather than the transit L3 devices.)

"Loose" is the sequence of hops the packet should pass through. It doesn't have to include all the hops, as the network will route to each hop. "Strict", though, require each and every hop, and they have to be connected. (In a larger network, the capacity of "strict" often is insufficient.)

BTW, for security reasons, many networks will not honor source routing.

[Jeremy Dubrulle]

Thanks for your answer Joseph.

I can't get it working.

Here is my network :

172.17.1.1 => 192.168.252.29 => 172.30.10.3 => 192.168.252.9 => 192.168.160.1

I want to ping 192.168.160.1 from 172.17.1.1

Everybody can ping everybody, but when I do a strict from 172.17.1.1 with : 192.168.252.29 172.30.10.3 192.168.252.9, it doesn't work

[Jeremy Dubrulle]

It seems like I need to put every IP that is used, even the 2 on a same switch to change the network ?

[Joseph W. Doherty]

If I remember correctly, for "strict" you would need to provide "192.168.252.29 => 172.30.10.3 => 192.168.252.9 => 192.168.160.1". For "loose" you only need to provide the final IP, the others are optional and don't need to be in sequence (assuming that the devices can route to them).

Again, if not working, remember many network devices disable "source routing" as a security best practice.