Visitor
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7 Messages
Suddenly my WAN IP lease time is only 2 hours
I have an ASUS RT-AC86U Router and NETGEAR CM1000 Modem. Nothing was change on my end when suddenly a few days ago I lost internet. After a few power cycles and waiting an hour or so, my internet came back up. However, I started intermittently losing internet.
After doing some digging, the only thing I noticed was that my WAN IP lease time was always 2 hours or less. This stood out to me because I know it used to be a 7-day lease. A few hours is really short, and any failure to renew in that time will result in a loss of internet.
Looking over my WAN settings on the router, I came across a "DHCP query frequency" setting which was set to the default mode of aggressive. However, a new mode called "continuous" was released in an Asus firmware update a year or two ago. I changed my settings to use this new mode and now my DHCP renewal seems to be successful every time within the two-hour window. Still, this seems like a Band-Aid fix and the real issue is the fact that Xfinity is only issuing me a 2-hour lease.
Any ideas? What controls how long a WAN IP is leased for? I would imagine that it is tied to the MAC address of my router but everyone I chatted with said that Xfinity only needs the MAC of the modem, not the router. I chatted with a few agents but nobody had any answers, and my modem has already been reset several times. The only thing I can think of is to get a static WAN IP instead.
flatlander3
Problem Solver
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1.5K Messages
3 years ago
The DHCP server is Xfinity's, so there isn't something you could do locally to change the lease duration.
Why the short 2 hour lease? Maybe they're exhausting the IP pool, or getting close, and that's their solution to free up IP addresses. Maybe they're working on the network by you, and left it short intentionally for testing or pending equipment swap.
Generally, your gateway should ride with it -- either renew the lease from the server cache, retry if a request fails, or change the IP if required. Good work on your part though. Not sure how you get past the customer service, and get to engineering but it is something they should be aware of if they are not. Could point out a broken device flooding their DHCP server so it's missing requests, or other network issue.
Perhaps Xfinity can post a number or offer a private chat to report it. If it were my network, I'd want to know.
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EG
Expert
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109.1K Messages
3 years ago
@B.Banner wrote: "The only thing I can think of is to get a static WAN IP instead."
To address this comment. You can only get static WAN / public IP addresses assigned with their Businesses Class Service, and when using their business class gateway device.
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B.Banner
Visitor
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7 Messages
3 years ago
The issue has returned again. Now I'm intermittently getting a 30 minute lease... 30 minute!!!!! When that happens, sometimes my router fails to renew it again within the next 30 minutes and I lose internet.
Why in the world would Xfinity be using 30 minutes as the lease time? This is getting crazy the only thing I can think of doing is reset the modem and power it off all night. Maybe this IP I've been assigned will go away and the next one will be back to normal.
If I can't get a static IP and I'm getting only 30 minute leases, this is going to be a serious problem.
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user_9a4d5e
Visitor
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1 Message
3 years ago
This seems to be a common long standing issue there are many chat logs out there like this. They all seem to be related to WAN DHCP timeout errors for customers with large home networks. I also have been fighting this issue for a while. Which is how I came across this chat.
Xfinity, why can't you identify this problem and resolve it?
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B.Banner
Visitor
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7 Messages
3 years ago
To rule out potential issues I decided to switch to a Motorola MB8611 since my Netgear CM1000 was showing as not supported by Xfinity. However, I still get a 2-hour lease and now today I had T3 timeouts.
Tue Mar 15 2022
Tue Mar 15 2022
Tue Mar 15 2022
Tue Mar 15 2022
Tue Mar 15 2022
Tue Mar 15 2022
Tue Mar 15 2022
Tue Mar 15 2022
Tue Mar 15 2022
Tue Mar 15 2022
Tue Mar 15 2022
Tue Mar 15 2022
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