Loopback on same network unreachable

[Michael_Goodlif]

Hi, I am trying to connect another switch to my network to segregate customer vlan's.

I am announcing my networks as /24's and want to create smaller subnets of these on another switch within my network. So for example create a loopback vlan with a /29 for a single client server connection.

I am testing this in my lab where I have a single network of 192.168.1.1/24. I have created a vlan "InputLB" which is set as loopback and has ipforwarding on. This vlan has 1 port which is active and is connected to the main 192.168.1.1/24 network. This InputLB vlan is assigned the IP address 192.168.1.33/29.

When I try to ping the 192.168.1.33 from any devie on my network, it will not ping. What am I doing wrong? Will this configuration be possible?

Thanks for any help.

[dflouret]

I'm not sure you can extend the superVLAN outside of a switch...

Take a look at Private VLANs (same doc, page 526). There's an example in page 539 that looks very much like the one you need.

[Michael_Goodlif]

Another quick question. There will be a vlan defined on my primary router, this will have a single connection to a new switch which has no knowledge of any configuration on the primary router.

The supervlan will be defined on the new switch on the port connecting the 2 switches. Then I will have individual subvlan's defined with ports for each customer's server.

Will this work?

primary router:
announces the /24
VLAN defined with a single connection to switch 2

switch 2:
supervlan defined on port linking to primary router, ip address assigned as x.x.163.1/24 gateway
subvlans defined for each client range with restricted ip's in x.x.163.1/24 range

[dflouret]

Nope, only for IPv4...

[Michael_Goodlif]

Thanks, that looks like it will do exactly what I want.

I have one vlan with the /24 defined, then I can assign loopback subvlans with restricted IP's to that. Just tested it and it seems to work. This is a great method of doing it as you don't waste IP's on broadcast and gateway, thanks!

Just one question, will this work with IPv6 too?

[dflouret]

You should create the individual /28 or /29 vlans (no overlaping, remember) and then advertise them as a single /24 vlan.

If you're using Extreme switches running EXOS there's a feature called L3 VLAN Aggregation (check https://www.dropbox.com/s/jjyypvv524anlg7/EXOS_Concepts_Guide_15_3_2.pdf, page 1247) that can help you accomplish something similar to what you want.

Daniel