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YamakasY
Silver

Routing between Vlans for internal traffic and over GW for internet (6024)

HI All,

I have a setup with a several of vlans that are like the following:

Vlan 1: 172.16.0.0
ip: 172.16.0.251

Vlan 4: 172.16.4.0
ip: 172.16.4.254

Vlan 8: 172.16.8.0
ip: 172.16.8.254

Vlan 12: 172.16.12.0
ip: 172.16.12.254

I have a router that is connected to Vlan 1 and had the IP 172.16.0.252 (Linksys WRT54G), just for Internet connection.

My hosts in each Vlan have the IP of their Vlan as their Gateway and DNS, this seems to be right. On Switch config level I have a route like:

ip route 0.0.0.0 0.0.0.0 172.16.0.252 

I also have RIP enabled on switch level.

When I want to ping something like google.com I see that the IP is resolved but I don't get any reply back. On the 6024 I get replies back.

On my WRT54G the routes to the vlan subnets are known and use the IP of the WRT54G as their GW, which also seems right to me.

What I see is that when I do a traceroute using a host on the 172.16.0.0 subnet, I always the the Linksys in the traceroute, which means all traffic goes in and out of the 6024, which is not nice at all.

I'm also not able to ping from other Vlans to other Vlans and I wonder why.

My config is kinda simple and I have seen them here a lot, but what can go wrong in such setup ? 

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40 Replies
Moderator
Moderator

Re: Routing between Vlans for internal traffic and over GW for internet (6024)

In order for the different VLANs to be able to communicate with each other, VLAN routing needs to be configured on the router. If you can post the running config of the switch, we can look through it and see if we can offer any advice on changes.

Daniel Covey
Dell EMC | Enterprise Support Services
Get support on Twitter: @DellCaresPRO

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YamakasY
Silver

Re: Routing between Vlans for internal traffic and over GW for internet (6024)

Hi Daniel,

Thanks for your reply. I have removed the configuration on my switch and want to start over.

Do you have any example of how to enable the Vlan Routing ? Maybe an example config so I can compare things ?

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Moderator
Moderator

Re: Routing between Vlans for internal traffic and over GW for internet (6024)

I am not sure if the wrt54g supports VLAN routing. If it does, then you can configure it to route between the different VLANs. If it does not then you would need to setup some static routes on the 6024, to direct traffic between the VLANS. Here is a white paper that describes setting up static routes on the 6024.

www.dell.com/.../app_note_38.pdf

Daniel Covey
Dell EMC | Enterprise Support Services
Get support on Twitter: @DellCaresPRO

Download our QRL app: iOSAndroidWindows

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YamakasY
Silver

Re: Routing between Vlans for internal traffic and over GW for internet (6024)

Hi Daniel,

Wasn't it the idea that the 6024 does recognize the Vlan Headers itself and use this to route from vlan to vlan ?

I have indeed read about the static routes, the WRT54G with DDwrt supports Static routes, I'm not sure about vlan routing but because this device is connected using a 100Mbps port against a 1Gbps I would like to avoid any travic between the vlans over this WRT54G.

Do you understand what I mean ?

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Moderator
Moderator

Re: Routing between Vlans for internal traffic and over GW for internet (6024)

The 6024 does not have the capability to route between VLANs. Regardless of the packet header information the capability is just not present on the device.

Daniel Covey
Dell EMC | Enterprise Support Services
Get support on Twitter: @DellCaresPRO

Download our QRL app: iOSAndroidWindows

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YamakasY
Silver

Re: Routing between Vlans for internal traffic and over GW for internet (6024)

OK, thanks. I have read on a lot of sites, and also the forum here, that this should be possible on the 6024. I also saw that the router function was not in the Vlan interface as a command.

You would say to add a static route for each vlan for my solution ? If this works, it would be great.

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Moderator
Moderator

Re: Routing between Vlans for internal traffic and over GW for internet (6024)

Adding the static routes should work fine for your situation. Reading through that White page it has a great scenario and examples of the commands that it takes to get those static routes to work.

Keep us updated and let us know what config you end up going with.

Thanks

Daniel Covey
Dell EMC | Enterprise Support Services
Get support on Twitter: @DellCaresPRO

Download our QRL app: iOSAndroidWindows

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YamakasY
Silver

Re: Routing between Vlans for internal traffic and over GW for internet (6024)

Hi,

Indeed, this document is the way I should do it.

What I wonder is what I shall do with the route and the vlan IP. My Vlan IP's are known and should be the gateway for the subnet as far as I know. The issue is that I get the following error in that case:

console(config)# ip route 172.16.4.0 255.255.255.0 172.16.4.254
Gateway cannot be one of the addresses configured on this device.

The document sets a gateway where the IP, .2 is not known in the config. I have seen this question a lot of times with no clear answer.

What do I need to use as an IP to use my Vlan as GW for my subnet ?




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Moderator
Moderator

Re: Routing between Vlans for internal traffic and over GW for internet (6024)

Alright, did some more looking at this, and it turns  out that the static routes we put in place cannot point to the switch itself. That is why in the white page the 6024 has the static routes going from VLAN to VLAN on other network devices.

We may be in a position where we would need a router on the network to perform the routing between VLANs. But I would like to see the running config you have on the 6024, we can look it over and see if there are any suggestions we can try.

Thanks

Daniel Covey
Dell EMC | Enterprise Support Services
Get support on Twitter: @DellCaresPRO

Download our QRL app: iOSAndroidWindows

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