SF300-24 Layer 3 mode routing problem

[Joshua Calandra]

Hi all, as subject, i've a problem with my SF300-24 routing. That's my network configuration:

Port 1 to 12 assigned to VLAN 10

Port 13 to 23 assigned to VLAN 20

Port 24 has an ip 10.17.7.254 to connect with my deafult route, beacuse I've also a Linksys RV042 router, connected in turn with my ISP router, having an ip 10.17.7.1.

VLAN 10 has 10.17.10.1

VLAN 20 has 10.17.20.1

So I add a default route on my SF300-24 to 10.17.7.1 to get Internet connection.

That's the problem:

Computer A is connected to VLAN 10 on port 1

Compuer B is connected to VLAN 20 on port 13

A e B can talk perfectly each other, and also to port 24 (10.17.7.254), but when I try to ping my Linksys RV042 (10.17.7.1) or reach Internet everything fail.

Instead when I logged into SF300-24 and try to ping Linksys RV042 (10.17.7.1) or reach the Internet, everything works fine!

What could be the problem?

Thanks,

Joshua

[Tom Watts]

Josh, the problem is, the router isn't as smart as we think.

Reference this post.

https://supportforums.cisco.com/thread/2123434

-Tom
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[Joshua Calandra]

So setting static ip in my RV042 resolve my problem?

[Tom Watts · Accepted solution]

Yes, need to set up static routes on the router.

-Tom
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[Joshua Calandra]

Ok, I'll try and let you know!

Thanks

[Joshua Calandra]

I set static route into RV042 to VLAN 20 (10.17.20.1) like this

Destination IP: 10.17.7.20.0

Subnet mask: 255.255.255.0

Default Gateway: 10.17.7.254

Hop Count: 15

So now when I try to contact net 10.17.7.0 everything goes ok, but when I try to contact Internet, by ping an external ip, it responds to me "Net Unreachable".

What can I do now?

I also tried to set in RV042 the default route like this

Destination IP: 0.0.0.0

Subnet mask: 0.0.0.0

Default Gateway: 10.17.7.254

Hop Count: 15

but I still can't contact external ip, but this time the message is "Time to live exceeded"

Thanks!

[Tom Watts]

Hi Josh, I just noticed an odd variable, you said your ISP modem is 10.17.7.x. This screws up a lot of stuff. That router won't know how to route any of the LAN subnets except what it is NAT'ing to...

The route you have in place seems okay since you've got communication up to the ISP box. But the problem is, when a request is coming back from the internet, the ISP box doesn't know how to send to the subnets it doesn't know about. You need to find a way to add the vlan 20 subnet in to the route table of the ISP box

-Tom
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