Ping function in 2950

[wrwiii122]

I have two Vlans on a 2950. VLAN1 is active management vlan. If I telnet into the switch shouldnt I be able to ping a device on any VLAN?

[Edison Ortiz]

You should, as long as the 2950 has a default-gateway command pointing to a layer3 device with that VLAN on its route table.

Keep in mind, 2950 is a layer2 switch. While it can have multiple VLANs on its database, the routing portion is done externally.

Please rate helpful posts.

Thanks

[wrwiii122]

Ok so what if it was a 3550?

Also I went to log into a 3550G and couldnt show run. Come to find out it was out of memory. I reloaded and everything is fine now. Why did that happen?

[Edison Ortiz]

3550 are layer3 switches. If you have a SVI for each VLAN on this switch up/up, then you should be able to ping each VLAN without the need for an external device.

I don't have an answer as to why you ran out of memory.

Please rate helpful posts.

Thanks.

[Richard Burts]

I fundamentally agree with Edison but would explain it in slightly different terms. The 2950 is a layer 2 switch and whle it may be configured with several VLANs it management interface is a member of a single VLAN. The management interface (which is where you are if you telnet to the switch) can access anything that belongs to the same VLAN as its management interface as a local resource. So the switch management interface can ping anything that belongs to the VLAN of the management interface. But to access anything in any other VLAN the switch management interface must get to some device that is doing inter VLAN routing.

HTH

Rick

[wrwiii122]

The 3550 wouldnt be smart enough to know it had a router connected to be able to ping other subnets connected through a router unless it had the gateway set to that router right?

[Edison Ortiz]

>>>>>>>>

The 3550 wouldnt be smart enough to know it had a router connected to be able to ping other subnets connected through a router unless it had the gateway set to that router right?

>>>>>>>>

Correct.

[sundar.palaniappan]

Hi,

To simplify things, if you have only vlan 1 int configured and you want the switch(s) to route traffic to other subnets then you have one of two options.

2950 - Layer 2 switch - Use default gateway to get to other networks.

3550 - Layer 3 capable switch - Use default gateway if ip routing is turned off. Use 'ip route 0.0.0.0 0.0.0.0' command to forward traffic to other networks.

HTH,

Sundar

[wrwiii122]

what does ip route 0.0.0.0 0.0.0.0 do?

I know it routes but why all the 0's?

[Edison Ortiz]

That's the gateway of last resort. It's for networks not listed in the routing table which are usually networks in the internet.

The 0's represent the 'don't care' bits. In English is like saying any network.

[wrwiii122]

So does it go to the gateway or is that the gateway. Does it try every address know or does it go to the default gateway?

[sundar.palaniappan]

Hi,

Just reiterating what I stated earlier, you would use the default gateway command when the switch is a layer 2 switch. You would use the default route, i.e 'ip route', command if ip routing is enabled in the switch.

In the second case the router would route traffic, like any other layer3 device, to any network based on the most specific match. If there's no specific match for that destination then it would use the default route, also called gateway of last resort, and route the traffic to that next hop address.

Hope that helps!

Regards,

Sundar