VLAN problem...help

[burleyman]

I am having a problem getting to one of my switches. I have three switches, a Catalyst 4506, 4006, and 4003. The 4006 is connected via fiber to the 4506...Gi 1/1 (4506) to Gi 1/1 (4006), and the 4003 is connected to the 4506 via CAT6...Gi 1/2 (4506) to port 3/1 (4003). The 4506 has many vlans configured, the 4003 is mostly VLAN 18 and VLAN 5, and the 4006 will be mostly VLAN 17 and VLAN 5. Right now I can get to the 4506 and everything attached can communicate to all other vlans in that switch and also can communicate to and from the 4003 switch with vlans 18 and 5. The problem is the communication to the 4006 switch (VLAN 17). When I an telneted into the 4506 switch I can ping the 4006 switch and when I am in the 4006 switch I can ping 10.15.117.200 on the 4506, but I cannot ping anything else from the 4006. I am still a little new to VLANs as I have not done too much with them. I am attaching the configs for all three switches....please let me know what I have missed or steer me in the right direction. If you need any more info please let me know. This is kind of urgent so any help anyone can provide would be great.

Thanks,

Mike

[burleyman]

Sorry forgot the configs.....

[Kevin Dorrell]

Mike,

I think your configuration is almost there. If I understand correctly, you are worried by the fact that when you ping things from the 4006 management CLI, you can only get to stuff in the 10.15.117.0/24 subnet. That is simply because you have not set up a default gateway in the 4006 to tell the 4006 management CLI where to send off-subnet packets. Try adding this line, and let us know if it solves anything:

set ip route default 10.15.117.200

Kevin Dorrell

Luxembourg

[burleyman]

Thank you very much it worked. I feel like a you know what....

I do have another question...Why don't I need the same think configured on the 4003 switch?

Mike

[Kevin Dorrell]

That is a bit of a mystery, isn't it. Unfortunately, I think your posting didn't include the 4003 config; we had the 4006 twice instead. I could take a longshot, and guess that the 4003 is configured with a mask of 255.255.0.0, and so is getting everything by proxy ARP, but I would probably be wrong.

Note that the gateway stuff we just put in affects only ping from the management CLI of the switch itself, and has no effect on traffic going through the switch. That's why I said your config was almost there ... I reckon your switches were working perfectly except for pinging from the management address.

If you have time, post the 4003 config, and we will see if we can work it out.

Otherwise, have a good weekend!

Kevin Dorrell

Luxembourg

[burleyman]

Here is the 4003...

Thanks again for your help.

Mike

[Kevin Dorrell · Accepted solution]

OK. You had the default route in the 4003 all along:

set ip route 0.0.0.0/0.0.0.0 10.15.1.225

Of course, because the management interface on the 4003 is on VLAN 18, (see the sc0 parameters) it needs to go through the VLAN 18 default gateway.

OK? Happy to be of help.

P.S. If it was useful, please don't forget to check "problem resolved" and rate the posting.

Kevin Dorrell

Luxembourg

[burleyman]

That is what I thought....but I tried to put that same thing in the 4006 and it did not work.....but all is good. Thanks for your help.

Mike

[Kevin Dorrell · Accepted solution]

I just noticed something even more interesting. The 4003 is misconfigured, but works by fluke. It is using 10.15.1.225 as a default gateway. This is actually off the VLAN 18 subnet, so it will ARP for 10.15.1.225. The 4506 will reply with a proxy ARP repsponse, thinking the 4003 wants to contact VLAN 1. But in so doing, it provides a MAC address that is valid for any routing, being that of the 4506.

It works, yes. But really, it should be using 10.15.118.200 as its default gateway.

Sorry, I missed that first time round.

Kevin Dorrell

Luxembourg

[burleyman]

I will make the change.....thanks.

Mike