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RT-AC5300 w/ Xfinity Gigabit - dhcp issues.

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It's not just about the lease, but about the actual "session". For example, my ISP will only give you one lease at a time. If I switch my router with another, it will be unable to obtain a DHCP lease unless I turn the modem off for at least 5 minutes. But regardless of this, if I put back the original router after a few hours, that original router will still obtain the same IP it used to have before. My ISP caches the lease it allocated to its MAC, however it just needs that 5+ minutes downtime before it will accept to assign me a new lease.

So if you are switching back and forth between two routers, you might need to have a similar 5+ minutes downtime (the length probably varies between ISPs, I've seen users on American ISPs go with 20 minutes just to be safe).

ok maybe I was not clear.

Modem: Motorola MB8600

Router: ASUS RT-AC5300

I have been using that combo for more than a year now, and the router worked flawlessly

until about 2, maybe 3 months ago, when suddenly the 5300 that has been connected to the mb8600 and working flawlessly - stopped working flawlessly.. that is when I COLD - POWER OFF - BOOT BOTH DEVICES, the only way to get the IP address from the ISP, I need to power on the modem, wait until it connects, then power on the router, wait for that to come up, then I have to reboot the MODEM again in order to get the IP address on the router.

I only swapped around routers to see if I could duplicate - I could duplicate using a different router with your firmware 384.12.. I had to power on modem, power on router, then power off then power on the modem..

If I use my TP-Link Archer C7 - this does not happen.

Oh, and I just spent nearly 3 hrs on the phone with Comcast - I am renting on of their new XB6 gateway devices.. I did this before y'all come back and say the modem is the problem... BUZZZZZZZZZZZZt... the exact same thing happened - the exact same thing happened.. Power on the MODEM, wait, power on the ROUTER - wait.. and wait.... and wait... and wait... NO IP ADDRESS.. I leave the router on and power cycle the modem, when it comes up I get the IP immediately.

so in summary.. two different modems, two ASUS routers - both behave the same way, does not want to get an IP address - and on a 3rd, non-Asus router, this problem does NOT happen..

Common denominator that I see: Asuswrt-Merlin 384.xx
 
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ok maybe I was not clear.

Modem: Motorola MB8600

Router: ASUS RT-AC5300

I have been using that combo for more than a year now, and the router worked flawlessly

until about 2, maybe 3 months ago, when suddenly the 5300 that has been connected to the mb8600 and working flawlessly - stopped working flawlessly.. that is when I COLD - POWER OFF - BOOT BOTH DEVICES, the only way to get the IP address from the ISP, I need to power on the modem, wait until it connects, then power on the router, wait for that to come up, then I have to reboot the MODEM again in order to get the IP address on the router.

I only swapped around routers to see if I could duplicate - I could duplicate using a different router with your firmware 384.12.. I had to power on modem, power on router, then power off then power on the modem..

If I use my TP-Link Archer C7 - this does not happen.

Oh, and I just spent nearly 3 hrs on the phone with Comcast - I am renting on of their new XB6 gateway devices.. I did this before y'all come back and say the modem is the problem... BUZZZZZZZZZZZZt... the exact same thing happened - the exact same thing happened.. Power on the MODEM, wait, power on the ROUTER - wait.. and wait.... and wait... and wait... NO IP ADDRESS.. I leave the router on and power cycle the modem, when it comes up I get the IP immediately.

so in summary.. two different modems, two ASUS routers - both behave the same way, does not want to get an IP address - and on a 3rd, non-Asus router, this problem does NOT happen..

Common denominator that I see: Asuswrt-Merlin 384.xx


So you don't have this issue with asus stock I managed to read in a post above, are you testing with the exact same settings selections that you are using on asus stock v.s. using on merlin-wrt ? for example, no custom scripts and no special parameters being used only available to merlin-wrt? I am only asking so we can make sure all variables have been eliminated.
 
So you don't have this issue with asus stock I managed to read in a post above, are you testing with the exact same settings selections that you are using on asus stock v.s. using on merlin-wrt ? for example, no custom scripts and no special parameters being used only available to merlin-wrt? I am only asking so we can make sure all variables have been eliminated.

I have been testing with bone stock firmware, whatever comes as the default, those are the settings :cool:
 
I have had these same issues.
Ac5300 & Arris sb8200.

I finally reverted.

Recently tried the newest fw...it was really disappointing...same sh*t
 
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yea I haven't seen these types of issues per-say firmware wise, but have seen these issues with a busted modem or poor isp services, the latter resulted in either a different modem or maintenance from ISP and the issues went away.

if you are getting issues with timeouts and whatnot in your modems log----whatever IP your modem uses could be 192.168.100.1, then it could very well be issues with communicating with your ISP, this could be a number of factors from a bad modem, to a bad signal from ISP.
 
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Had this same issue. Resolved it by cloning the MAC address of my computer. No issues since.
This is a good option to try, but first it would be best to test if the modem reproduces the same behaviors while being only connected to the computer ( for a couple of days to thoroughly test).
 
I had same issue. Same cable modem! Cloning MAC did not seem to help.
Tried a Negear ax12 router. Similar. Said WAN cable unplugged or something like that. That was truly a POS router! They will get a lot of returns.
The fix that seems to work for me was the "Restore Factory Defaults" in my Moto cable modem. And disabling "Networking Monitoring" in my 86U. Current uptime is 2 days 11h:20m:11s
Was getting that red light of death everyday.
Check you cable modem logs. It is a caused by modem, not the router. Check modem signal levels too.
 

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