VLans

[GSXdan]

When you set up a VLAN between 2 hosts on a switch, can they/are they supposed to ping each other? Both workstations can ping the router, but they can not ping one another. Each workstation is on its own VLAN. We are using a CISCO 2501 series router with a CISCO catalyst 2800 series switch.

Thanks ^dan

[mbossman2]

I am assuming that both hosts are on different subnets:

The answer is no.

the switch you have does not support layer 3 functionality so there is no capablity for inter-VLAN routing.

I am not sure if the Cisco 2501 offers 802.1q trunking which would allow you to use the single ethernet port to carry both VLAN's and have the router act as the inter-VLAN router.

[GSXdan]

the hosts are on the same subnet(this is just a lab for my cisco class). but i read somewhere that says that if you set up a secondary ip on the router, they should be able to ping each other. here is the setup we have going here:

Cisco 2501 router(E0 = 192.5.5.1) > Cisco Catalyst 2800 switch ( 2 VLANS w/ ip addresses of 192.5.5.3 and .4) > host 1(192.5.5.10) and host 2(192.5.5.11)

i configured the router with a secondary ip of 192.5.5.2 but the two hosts still cant ping each other.

does this have anything to do with the firmware? there is standard edition and enterprise edition, we have standard here. any help would be great.

thanks ^dan

[mbossman2]

ahhh....that makes a big difference on the switch. the -A variant does not allow for VLAN trunking, that is a feature of the -EN variant of the switch, you will have to upgrade to the EN image for the switch. Which switch in the 2800 series do you have and what feature pack are you running on the router?

If you are not sure on the switch, can you get me the serial number and I can confirm for you enterprise or standard load on the switch.

[UncleS]

Couldn't you set up sub-interfaces on the E0 to route between VLANs?

[GSXdan]

the switch is just a Catalyst 2800, and the serial number is: 280289740. we tried to set-up sub-interfaces, but since we have not learned how to do that yet, it was a little difficult and we didnt get it.

thanks ^dan

[mbossman2]

The 2802 is an ancient switch. I can find very little information on that switch. It appears that this switch has Cisco TAC support, you may want to call in and have them help you out.

[GSXdan]

since we need the enterprise software, that problem is solved, but i just have a question now...

attached is a picture of a vlan that spans three switchs. how do you set up this kind of vlan? all i need is a explanation of how it works, not commands to actually set it up. i just dont understand how that works.

thanks ^dan

[mbossman2]

based on your drawing, you would put each of the "groups" on their own subnet. Engineering on subnet A, Marketing on subnet B etc. You would then group the ports together to form a logical network. at this point, the anyone on the engineering LAN would only be able to see users on the same LAN (IE floor 3 PC, floor 2 PC and floor 1 Server, in the engineering ellipse). The router in your diagramcan be programmed to:
allow users to pass from one logical network to another unfettered (which kind of defeats the purpose)
or
you can limit the types of traffic and requests (for example, you can program the router to only allow email requests/sends).

[piasabird]

What if you set up a dhcp server to route then to the other vlan?

[mbossman2]

a dhcp server has the ability to distribute an IP address to a networked device, but generally a device can only belong to a single subnet (unless you have multiple adapters, then you can bind each one to its own network). A router, being a layer 3 networking device, allows traffic to flow from one IP subnet (layer 3 network) to another.