Inter VLAN communication in Cisco Catalyst 4507R

[heyyunus]

Hi,
I have a Cisco Catalyst 4507 switch with Supervisor engine II. My default vlan is in ip 10.4.0.3/16. I have created two more VLANS with id 2 & 3. When I assign the port of the switch VLAN 3. Then communication between VLAN 1 & 3 stops.

I have setup the default route 0.0.0.0 0.0.0.0 10.4.0.2 where 10.4.0.2 is another router.

How can i enable communication between VLAN1 & 3. The idea behind this is to prvent the broadcast in one VLAN to another. for this purpose I have enabled VTP in server mode and also enabled VTP pruning.

I know i cant assign an IP to the VLAN interface because it will then overlapp with the default VLAN 1.

What am I missing??


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Yunus

 

[chipk]

An IP is necessary on the vlan in order for inter-vlan communication. If your addresses are overlapping, that's another problem.

 

[vipergg]

Create a layer 3 SVI for each vlan that does not conflict with your current address scheme . Each network must have its own address space that does not overlap . Make sure ip routing is turned on .

 

[heyyunus]

Hi,

Thanks for the reply, but here i cannot change the second subnet as it has to be 4, thats the way our network is designed for my location, the 2nd subnet is different based on the the geographic location.

The idea is to just prevent the broadcast, how can i achieve this.

will the IP unnumbered command help me in this case??


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Yunus

 

[chipk]

ip unnumbered is not going to help you in this instance. You still need another IP segment with an address range that does not overlap.

 

[heyyunus]

Ok, i got the approval for using subnetting in the 2nd octet. I am going to use 10.54.x.x, 10.55.x.x, 10.56.x.x. I am going to give the following commands to make it work. Please see this and correct if any mistakes are there:--

# conf t
conf# int vlan 2
conf-if#ip addr 10.54.0.1 255.255.0.0
conf-if#exit
conf# int vlan 3
conf-if#ip addr 10.55.0.1 255.255.0.0
conf-if#exit
conf# int vlan 4
conf-if#ip addr 10.55.0.1 255.255.0.0
conf-if#exit
conf#ip routing
conf#ip route 0.0.0.0 0.0.0.0 10.4.0.2
conf#Ctrl+Z
#

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Yunus

 

[baddos]

Those are really large subnets for your broadcast domains. Is there a need for that many hosts?

 

[heyyunus]

I realized that and made the following changes:-
10.54.1.x / 24
10.54.2.x / 24
10.54.3.x / 24


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Yunus

 

[vipergg]

Much better subnetting using a /24 and is pretty much a standard that works very well .