Peplink Balance 300 with Comcast Xfinity - not picking up DHCP configuration

I’ve had Peplink 300 for ~5 years, and I love it. I’ve been using it with multiple ISP’s but all with a static IP configurations, and no issues. I just moved to a new house, and I’m trying out residential service from Comcast Xfinity and it works great if I plug it directly into one of my computers. But if I plug it into a WAN port on my 300, it never acquires the IP settings via DHCP, even when configured to do so. I’ve tried varying MTU, just about everything, nothing works. Is there a secret out there I don’t know about? Any help would be appreciated.


  • Jeff

Figured it out. It has to do with the way the provider (Comcast) caches the client MAC address the cable modem is connected to. There is a order of operations. The modem basically needs to be reset to clear that cache and then connected to the 300. Everything works fine now. Learning experience from moving from static to dynamic IPs.

Thanks Jeff,

Having 5 years of experience with Peplink you must have a story to tell :slight_smile: Feel free to share it with us and be in for a chance to win our latest Surf On-The-Go. Read more at


Actually, I don’t have a lot to say. In all this time, I’ve only had one issue with the 300, having to deal with some services and logging, etc. Outside of that, things have been rock-solid and smooth. I think that is a testament to the Peplink’s quality actually. Simple to use, reliable and powerful.

Thanks Jeff,

That is pretty much how most of our users feel. If we want to be in the draw to win our latest Surf On-The-Go, go ahead and post this on our wall and like us on Facebook.


Since I have the same problem I thought I’d piggy-back on this thread.
Configuration:Balance 30

[INDENT=2]2 sonic lines. Speed some 25 Mbps each. Static IPs
1 Comcast line, through a Netgear CM 500 DOCSIS 3.0 cable modem. Speed some 170 Mbps. Dynamic IP
All live
1 Verizon wireless modem line as backup.[/INDENT]


If the router or the Comcast modem goes down (e.g. a power outage) then router does not pick up the Comcast line when power returns (it hangs on “connection…”). It picks up the Sonic lines.
The comcast modem reports that all is well on its end (cable connection up, ethernet to router is up and there’s traffic.

Unacceptable hack:
If I unplug/replug the Comcast modem then the router does complete the connection.
This is unacceptable because it assume that I am at the network rack when the system is supposed to come up again.

Solutions or suggestions?


Need you to elaborate more on the problem below.

  • Router is referring to Balance 30?
  • Why you still need Balance 30 to choose Comcast line when connection is down?

I suspect the problem you are facing is related to the settings. Please open ticket for us to take closer look.

The router is the Balance 30.

My apologies for the imprecise writing w.r.t. the Comcast line not connecting to the router: Should have been “When the router or the Comcast modem goes down, the router does not pick up the Comcast line when power comes on again.”

I’ll open a ticket later today.

I f your router isn’t picking up DHCP configuration then you may login into the admin settings of your router to configure it properly

Thanks for the pointer.

However, in this case there is no comcast router (only an Arris cable modem). The peplink B30 was the router.

We have replaced the Arris modem and upgraded the Balance (to a 380). The problem is now gone.