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7 Messages

Monday, January 31st, 2022 7:09 AM

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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.

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3 years ago

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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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B.Banner

Visitor

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7 Messages

@flatlander3​ That's what I was thinking was that there is some work being done in the area because they are laying down the ground work for new homes near me. At least my router with the continuous mode seems to be handling it now. No drops at all today but I did check and it's still only a 2 hour lease.

I think you are right that someone knows but the question is how to get up to that level and I don't like talking on the phone.

3 years ago

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flatlander3

Problem Solver

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1.5K Messages

@B.Banner​ Work in your area makes sense.  Maybe they're going to cut you over to a new subnet.  Redirecting DHCP requests so you get new IP's while leaving both routes working is one way to do it.  They would get testing that way too before the cut over.  Could be you're just routed through temporary gear if the subnet didn't change while they fix something else.

Maybe you just got unlucky too and your router doesn't handle that well, or the DHCP server was actually down or rebooting and your router firmware got stuck and flaked.  It's supposed to retry at various not so random intervals on a timeout or failure, but I'd guess the firmware on these things isn't tested all that well.  2 hours is still a valid lease time.  It really shouldn't matter what it is if everything and all devices play nice together.  You'd never notice a lease renewal and that's usually what happens.

In any case, maybe just leave the "constant renewal" setting until you see the lease times go back to normal since that's working for you.  It's not all that Zen, but the traffic is pretty harmless and Xfinity does approve 3rd party firmware so I wouldn't feel bad about it.  Maybe change it back when you see a week long lease just to be nice and cut down on the overall network chatter, and chance of DHCP collision with other people's stuff.

3 years ago

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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.

(edited)

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B.Banner

Visitor

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7 Messages

@EG​ That's unfortunate. I was chatting with an agent last night and he said to call 1-888-565-4329 and there would be no issue getting a static IP, no business account needed. ☹️

3 years ago

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EG

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109.1K Messages

@B.Banner​ 

That was incorrect. Their residential service assigns only dynamic public IP addys.

I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick

3 years ago

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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.

(edited)

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XfinityBillie

Official Employee

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3.1K Messages

Hello and thank you for taking the time to reach out to us here on our Xfinity Forums! I'm truly sorry to hear that you've had continued frustrations with your internet and I would love to look into this further with you. Please send us a direct message to "Xfinity Support" with your full name and address to get started.

 

To send a direct message you may need to:
Click "Sign In"
Click the "direct message" icon
Click the "New message" (pencil and paper) icon
Type "Xfinity Support" in the "To:" line and select "Xfinity Support" from the drop-down list which appears. The "Xfinity Support" graphic replaces the "To:" line
Type your message in the text area near the bottom of the window
Press Enter to send it

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
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3 years ago

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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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CCStephanieK

Problem Solver

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909 Messages

Hello, @user_9a4d5e. I would like to look into the logs further with you to help figure out why it's renewing the IP lease for you so frequently and see if we can figure out what may be causing the errors. Please send us a Direct Message with your first and last name. The message icon is located at the top right of the Community Forum page, clicking on the message icon will allow you to initiate a chat conversation with us directly. Please ensure you are sending your message to our 'Xfinity Support' handle. 

I no longer work for Comcast.

3 years ago

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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.

 Event Log  
  
    Time    Priority    Description 
    11:36:22
Tue Mar 15 2022		   Critical (3)   Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
    11:36:22
Tue Mar 15 2022		   Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
    11:36:24
Tue Mar 15 2022		   Critical (3)   Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
    11:36:24
Tue Mar 15 2022		   Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
    11:36:27
Tue Mar 15 2022		   Critical (3)   Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
    11:36:30
Tue Mar 15 2022		   Critical (3)   Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
    11:36:30
Tue Mar 15 2022		   Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
    11:36:35
Tue Mar 15 2022		   Critical (3)   Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
    11:36:35
Tue Mar 15 2022		   Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
    11:36:38
Tue Mar 15 2022		   Critical (3)   Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
    11:36:38
Tue Mar 15 2022		   Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
    11:37:25
Tue Mar 15 2022		   Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;

(edited)

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XfinityAlfonso

Official Employee

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1.5K Messages

Hello @B.Banner are you still seeing these T3 Timeouts on the MB8611? Have you gone back to the CM100 with similar results? We are always here for you as a resource and would love to look into the account further with you. 

 

To send a "Peer to peer" ("Private") message:

Click "Sign In" if necessary

• Click the "Peer to peer chat" icon

• Click the "New message" (pencil and paper) icon

• Type "Xfinity Support" in the "To:" line and select "Xfinity Support" from the drop-down list which appears. The "Xfinity Support" graphic replaces the "To:" line

• Type your message in the text area near the bottom of the window

• Press Enter to send it

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick

3 years ago

0

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