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Identical VLAN gateway config on multiple L3 switches

Identical VLAN gateway config on multiple L3 switches

PS
New Contributor
I'm trying to fix a mess that I partly inherited and then exacerbated through ignorance.

We have three X450e-48p switches on a single, flat, /24 network, one per building. One of the switches has a small port-based VLAN but essentially everything else is on the Default VLAN so we may as well have been using L2 switches all this time. Anyway, I need to get this thing under control, so:

The default gateway for basically everything in this 10.10.10.1/24 network is the firewall's ip address. The three switches have ip addresses of 10.10.10.150, 10.10.10.151, 10.10.10.152 which are used to manage them.

Can I create an identical VLAN on each switch such that the default gateway for that VLAN is the same IP address no matter which switch the host is plugged into?

Like, on all three switches can I blow away the VLAN configuration and do this:

create vlan voice_vlan
configure vlan voice_vlan tag 11
configure vlan voice_vlan ipaddress 10.10.11.1/24
configure vlan voice_vlan add ports 1-48 tagged
enable ipforwarding voice_vlan

configure vlan default ipaddress 10.10.10.1/24
configure vlan default add ports 1-48 untagged
enable ipforwarding default

I assume this would create a problem with management access so, given we don't have any dedicated management network to speak of, how would I then manage the switches?

12 REPLIES 12

PS
New Contributor
That is really helpful, thank you.

When you say the default gateway on each switch must be different do you mean a host on switch B in the users VLAN must have their default gateway set to 10.10.10.2 and another host on switch C in the voice VLAN must have theirs set to 10.10.11.3, or are you talking about the different "configure ip route add default x.x.x.x" commands? If it's the former I guess I didn't understand as well as I thought I did.

Drew_C
Valued Contributor III
You're welcome. Glad to help!
Let us know if you need anything else.

PS
New Contributor
I know this is like Switch Configuration 101 so thank you for bearing with me as I attempt to remember basic concepts I apparently forgot years ago!

I hope this thread will be useful to others who find themselves in a similar position of having to fix something that has been sadly neglected for too long. Thanks for everyone's contribution.

Drew_C
Valued Contributor III
Sorry for not mentioning that... Your hosts will still use the .1 as the gateway for each VLAN. I was just referring to the different
code:
configure ip route add default x.x.x.x
commands for switches B and C.
GTM-P2G8KFN