VLAN help

Hi there,

I'm studying for my CCNA and am messing around with a few different
VLAN scenarios.


Up until now, we have been taught to use different subnets for each
vlan.


e.g.
VLAN2 > 192.168.2.x
VLAN3 > 192.168.3.x


However, I would like to see what happens when you have different
VLAN's on the same subnet.


So, I've got two hosts;


Host A is on VLAN 2 and has an IP address 192.168.4.3/24
Host B is on VLAN 3 and has an IP address 192.168.4.20/24


I've configured the ports on the 2950 to enable static VLAN's for the
two ports. Up until now, there is no problem...Host A can ping other
hosts that have been assigned onto VLAN 2 and Host B can ping other
hosts on VLAN 3. Neither can ping each other.


But, I'd like to configure inter-VLAN routing. Is this not possible
because they are on the same subnet?


I've connected and configured a trunk link between the 2950 switch and
a 2600 router, and set;


2600(config)# interface f0/1
2600(config-if)# no ip address
2600(config)# no shut
2600(config)# interface f0/1.2
2600(config-subif)# encapsulation dot1q 2
2600(config-subif)# ip address 192.168.4.1 255.255.255.0
2600(config-subif)# exit
2600(config)# interface f0/1.3
2600(config-subif)# encap dot1q 3
2600(config-subif)# ip address 192.168.4.19 255.255.255.0


However, Host A can ping both 192.168.4.1 and .4.10, whereas Host B can

ping neither addresses.


Is it not possible to enable inter-vlan routing this way, or am I doing

something wrong? I assume the problem is because you are assigning two
subinterfaces on the same subnet on the router, but I thought that with

the dot1q x command you were speciyfing that only VLAN x could
communicate with it?


Would appreciate an explanation!


Thanks,
Dilan

.

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