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Cisco SG300-10 & FiOS Actiontec Router

Hello all.  I just received a new Cisco SG300-10 and am configuring it in Layer 3 mode.  I am trying to setup multiple routed VLANs going back to a FiOS Actiontec router.  My configuration is as follows.

Fios Router:

Assigning DHCP through 100.

SG300-10 has VLan 1 ip used for Mgmt.

VLAN2 is

VLAN3 is

I have a static route set on the fios router for both subnets setup as follows.

Destination Gateway Netmask Metric 1

Destination Gateway Netmask Metric 1

I have a laptop connected to Gi8 on the Cisco (Vlan 3) and statically assigned, with a gateway of  DNS set to the fios router ( 

Everything pretty much works EXCEPT, I cannot get out to the internet from either vlan.  Traffic routes between vlans/and the default subnet on the fios without issue.

When I ping out, DNS resolves, but will not go past the fios router.  Am I missing a setting somewhere?



David Hornstein
Rising star

Hi Chris,

Can that FIOS router also NAT  network 10.0.3.x  and 10.0.2.x network.

DNS resolves as you are sending DNS requests to the FIOS router,  If you were to sedn DNS requests to a DNS on the internet, I would doubt you would get a response.

I think you have to fi9gure how the FIOS router can NAT and Firewall these two extra network.

regards Dave


I think you are 100% correct - and I think I found a way to NAT the 2 subnets.

I setup a seperate "Connection" (Thats what its called in the fios router) and assigned it IP and respectively (I think this adds the subnet to the NAT).  I was also able to setup the Fios Router DHCP server to assign for those subnets.  This allows me to get out to the internet and route between subnets, however the problem I have now is the clients cannot pull an IP via DHCP.  Im pretty sure I just need to setup the DHCP Relay option on the Cisco, but am unsure how exactly to do so.  Any help on that would be much apreciated!



Hi  Chris.

Under the  IP configuration TAB is a section on DHCP replay.

I actually clicked help and it bought up the second screen capture below..

The question on my mind is how can this FIOS router differentiate a DHCP request from VLAN2 or VLAN3.

We offer option 82 informaton out to the routers, so the router would know which VLAN the DHCP request is coming from.

So,  on the screen below enable DHCP Relay, maybe if you can use it, tick option 82.

Then select the tab  DHCP relay interfaces,  and  add the two VLAN  interfaces that you wish to be relayed

let's see how you go .

regards Dave

Thank you!!!  Great help!

You already know

I assume you have default route on the SG300 switch pointing to your FIOS router.


You may need to add an ACL on the FIOS router for the layer 3 networks to allow them on the internet.  A lot of routers only allow DHCP networks setup on the router outside so you need an ACL to allow non-DHCP networks out on the internet.


I assume your are using an access port for your layer 3 connection to the router.