How can I get 2 VLAN's to communicate with each other

[whiteford]

Hi,

I'm just setting up a lab, I have 2 VLAN's on a Cisco 2950, one for servers and one for users. Both VLANS are on different subnets:

Users: 192.168.1.x/24

Servers: 192.168.2.x/24

Would I have to make the VLAN's layer 3 and give each VLAN an IP and add some sort of static route?

Thanks

[glen.grant]

Yes , one port on the router set up with subinterfaces for each subnet and the the 2950 side port set up to trunk with the trunk forced on "switchport mode trunk" . This will route all vlans between each other.

[whiteford]

What a great idea, I'm studying for my CCNA and someone told me youdon't need to learn scenarios like this but I think it helps. Am I gettign ahead of myself, trunking is part of the CCNA I beleive?

[glen.grant]

Trunking is part of everyday life in networking and absolutely something you should know like the back of your hand . :-)

[whiteford]

So the 2950 and the 1721 or 2620 will need to support dot1q trunking? How can I find this out as I will need to upload the correct IOS.

[VictorAKur]

its easy enough to find out - try to configure a subinterface as per one of the posts in this thread. If it accepts commands - it is supported. If not - go on cisco.com and look for the minimum version for your hardware with required support.

[whiteford]

Here are my configs, I have the routers FE 0/0 port plugged into the switches FE 0/1 port.

A laptop in the switches FE 0/9 VLAN 10 - 192.168.2.50/24 gateway of 192.168.2.1

A laptop in the Switches FE 0/17 VLAN 20 - 192.168.3.50/24 gateway 192.168.3.1

They can't ping each other or their own gateways, have I missed something?

Switch#sh interfaces fastEthernet 0/1 switchport

Name: Fa0/1

Switchport: Enabled

Administrative Mode: trunk

Operational Mode: trunk

Administrative Trunking Encapsulation: dot1q

Operational Trunking Encapsulation: dot1q

Negotiation of Trunking: On

Access Mode VLAN: 1 (default)

Trunking Native Mode VLAN: 1 (default)

Voice VLAN: none

Administrative private-vlan host-association: none

Administrative private-vlan mapping: none

Administrative private-vlan trunk native VLAN: none

Administrative private-vlan trunk encapsulation: dot1q

Administrative private-vlan trunk normal VLANs: none

Administrative private-vlan trunk private VLANs: none

Operational private-vlan: none

Trunking VLANs Enabled: ALL

Pruning VLANs Enabled: 2-1001

Capture Mode Disabled

Capture VLANs Allowed: ALL

Protected: false

Unknown unicast blocked: disabled

Unknown multicast blocked: disabled

Appliance trust: none

[VictorAKur]

Well... you do have the Native VLAN 1 on the switch and VLAN 10 in the same network range - 192.168.2.0/24. Change the IP range of one of the VLANs. In fact you can shut down the VLAN 1 interface completely, unless you are planning to use telnet to connect to the switch in the future.

Have a look here:

http://www.cisco.com/en/US/tech/tk389/tk815/technologies_configuration_example09186a00800949fd.shtml

All you need really... :)

[whiteford]

I will test with no VLAN1, however how would I set the switch up so I could telnet to it as well?

Also how did you find that link, I did a search and found nothing! :)

[VictorAKur]

You cannot take the VLAN1 off the switch (not 2950 any way) all you can do is to either admin down the VLAN1 interface, or change the IP range.

To telnet onto it configure a third subinterface on the router with the IP range of the VLAN 1 interface (that is if you choose the VLAN 1 as your management VLAN, typically it is advisable to configure a VLAN with some random number to be your management VLAN, for security sake).

How did I find the link? :) It is easy enough - go to http://www.cisco.com and type something like "inter vlan routing" in the search field :)

I think cisco.com is a VERY good place to look for networking solutiuons.

[whiteford]

I guess it's knowing what to look for like "inter vlan routing" it's difficult if you don't know the correct wordind somtimes :)

I will configure a differnt VLAN and give it the same range as what WLAN 1 was or VLAN 10 for the users as that's where I will be.

[whiteford]

A little progress, the trunk is nearly working I think.

I have a PC (PC A) with:

IP address - 192.168.2.50

Gateway - 192.168.2.1

In Port 9 of switch

I have a PC (PC B) with:

IP address - 192.168.3.10

Gateway - 192.168.3.1

In Port 17 of switch

PC A can ping 192.168.2.1 and 192.168.3.1

PC B can ping 192.168.3.1 but NOT 192.168.2.1

What could this be?

[whiteford]

Hi,

I'm not sure my Cisco 2620 (45 or 48mb mem) can to trunking, would it me the same trunk commands as the switch?

Trying to look for an IOS with not much luck.

[whiteford]

Actually it does, just downloaded the correct IOS.

[VictorAKur]

Check the IP addresses on your VLANs 1 and 10 - they are in the same range. If it could't do trunking it wouldn't have accepted the commands.

[mbawar677]

One question 

How to connect two different VLANs in same subnet by using Router or L3 Switch?

example;

 Pc1: 10.0.0.1——vlan 10

pc2 : 10.0.0.50 vlan 20