I have a question regarding if a switch or router is the way to go in my situation. We have a modem through Comcast that only has one available port on it right now and we are getting a VOIP system through RingCentral. We are receiving 5 phones that support PoE, most routers I am finding either don't support PoE or they only have 4 ports on them. Can I plug the Switch into the open port on the Modem and have all of them work like they should?

  • If the phones are to run on the same network as the other devices, this should be fine in theory. However without knowing the design, devices (makes/models), or actual current setup, we can't really answer this definitively.
    – YLearn
    Jun 13, 2014 at 14:56

1 Answer 1


Switches are where you typically find PoE especially in enterprise-grade equipment. You should have no issue extending your LAN with a switch on an available port on your cable modem, but you really should have a router/firewall function sitting between your LAN and the WAN from your modem to protect your network.

You can confirm that you are directly connecting your LAN to the modem by the presence of public IP addresses which is a good way to get hacked. A firewall provides a baseline of protection that you seem to be lacking now. Be aware that the firewall (on your router) will be providing a NAT function that doesn't always play nicely with SIP packets from your VoIP. You may need a firewall capable of handling SIP properly or a VoIP system that can support STUN.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.