SF1200 won't pull DHCP on WAN

Technical Support for Routers
1

Is there a trick to get this new unit to pull DHCP on WAN? upgraded to 3.204. Same cable to my laptop pulls public IP from the modem, other routers pull DHCP public IP from the modem.

Nice new toy but embarrassing me in front of the client lol. What to do?
Temporarily using a Slate but need the switch of the SF1200…

Set the Internet to DHCP, hit apply, states ‘success!’ but never gets ip or connectivity.

2

OK … ten minuts later I have DHCP on WAN …

No clue what got it to go, had restarted modem and router numerous times, finally one restart got DHCP. I’m not touching it :]

3

The problem is the ISP modems.

An ISP modem, always lock the mac address of the connected router (pc).

So when you want to change to a new router, the new router will not be able to get IP from the modem, because the modem is not issuing the IP.

For some modems, if you do a reboot of the modem, it will accept new routers. But this may not be true for all modems. Some modems, takes much longer to access new routers. The modem in my office, takes at least one hour. So we just turn it off and leave for lunch. When we come back the router got IP address.

One quick way is, you clone the mac address of your old router to the new router, it will work immediately.

If mac clone is not a choice, here is the correct way:

  • Reboot your modem and try new router.
  • If cannot get IP address, turn off modem for 10 minutes (some modems takes longer), then turn it on again to try
  • If still cannot get IP address, call your ISP and tell them you need to change router and the modem is not issuing IP. So they will reset for you.
4

This makes sense, thank you. Exact behavior, except service provider restart made no difference, had to wait. Time was required to reset, about 10 minutes in this case.

Reinforces the concept of patience … we get spoiled by some instant responses and fail to realize patience is necessary in networking. Many times I just sit and wait for the eq to finish what it’s doing and all is well.

Thanks for reminding me of the mac clone, great for instant gratification hihi.

Is this for routers only though? I had set up my laptop for DHCP and it pulled a public IP immediately. Does the ISP ‘know’ that a router vs a pc has connected?

5

It should work for both routers and pc. Not sure about your case, but from our test, pc does not get IP immediately as well.