Question Router is suddenly unable to release/renew Dynamic IP ?

May 1, 2022
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Hello everyone,

I've posted this on the community forums for my router manufacturer, (TP-Link Archer A7) but I wanted to also post it here to see if I could get any answers. I've been having this problem for about 48 hours now, and I really need my internet for work, so it has been an issue, although at least there is a way to temporarily fix it, as I will outline below. Thank you for any help anyone might provide.

For about 48 hours, my Archer A7 semi-randomly loses its connection to my ISP. I say "semi-randomly" because it consistently does it between every 4-5 hours. I can't get an exact fix because I'm usually not using the internet right at the time it fails (or noticing that it has failed) but it is definitely between 4-5 hours after the last router reboot or manual release and renewal of the Dynamic IP.

After dealing with this several times during the workday Friday, I called my ISP to get some help the next day. Just in case maybe it was a modem problem. However, it wasn't, and they confirmed that the last time my router had asked for a new lease had been earlier that morning, and that it definitely should have asked for one a couple more times since then, but it did not. My ISP could see some data and determined that it looked like the router was not picking up a new IP lease when it should, thus determining that I had no internet access. Again, a manual reboot of the router or my manual releasing of the IP fixes this issue, until the next interval 4-5 hours later.

The modem is from my ISP, and I am unsure of its make and model. Unfortunately, they put it in when they installed fiber about a year ago, and it is in a difficult place for me to reach (I've a mobility impairment and it requires some crawling to get to where the modem is). The Archer A7 router is not from my ISP, it was a gift at the beginning of the year and has worked very well till now.

There are typically 4 devices that use my router: A console, a laptop, a tablet, and a smartphone. I mention all of this stuff because I read the stickied thread on how to ask for help and thought it might be relevant.

Based on talking with my ISP and some of the fixes I found on the community forums for the manufacturer, we decided I should change the lease time from the default to something else. I shortened it to an hour, but this didn't help. I wondered if perhaps the router was having trouble renewing the IP after a certain number of successful renewals, so I then set the timer to the ludicrously low number of 6 minutes, wondering if perhaps it would fail to renew after a few tries/minutes instead of the usual 4-5 hours. This didn't help either. Which, given my limited understanding leads me to believe that the router has no problem releasing and renewing the IP as many times at it wants for the given lease time. It always stops doing it at the 4-5 hour mark regardless of how often it needs to perform the renewal. It is as though the router is fine doing its job for 5 hour intervals and then just refuses, requiring me to manually release and renew the IP as some kind of "break" for it so that it resets that timer.

I suppose it could be faulty, but it is only a few months old, and it is odd that it is perfectly capable of doing its job for several hours after a reboot or manual release.

A few other things:

I didn't change any settings recently prior to this problem starting. In fact, haven't needed to do anything to it since getting it until now.

It did need a firmware update, which I did, though this did not help. I also reset the network again completely and set it up again. This also didn't help. I read some threads where some people felt that rolling back the firmware solved their issue, but mine was occurring before I updated the firmware. This is the first time I updated the firmware since I got the router. It is now running the latest firmware.

Got a new cable for the connection between the router and modem just in case a physical connection was faulty, also no help.

I have not changed the lease time to a much longer time than the default, yet, but based on the fact that it doesn't seem to care when the lease is up, only when the 5-hour mark has passed, I am not sure this would do anything.

I've also found out that, although manually releasing and renewing the DHCP fixes the problem for about 5 hours, doing this in the middle of the previous reset does not extend the "timer". For example, if the router fails to release and renew at 6p.m., and I decide to release and renew at 8p.m., it will still fail to release the IP at around 11p.m., 5ish hours from the last time it failed to do so, even if I did a manual release and renew in between then. It is as though the router feels it must wait that allotted time before it decides to not release and renew.

With no problems for the modem, either, I'm at a loss as to what to do. It could be I need to replace the router, but since I use the internet for work, I wanted to try every possible thing first.

I do plan to report back to my ISP next week, but I also wanted to check here to see if anyone else had any ideas.

Thank you for reading.

That's about it, although I am happy to provide any additional information. I can post logs once I get back to the computer later tomorrow, although I am not sure how to read most of the information in the logs or if it is safe to share, perhaps someone can tell me. For what it might be worth, there's no log activity except for several entries dated from before I got the router (weird) and then several entries from when this started happening, and that's about it. I know this a rambling post, and I am sure I've forgotten something important that you need to know in order to help. I'll try to get back to this thread tomorrow to check any replies and do what I can. Thank you.
 
I am somewhat unclear as what IP address you are losing. DHCP does not function the way you describe.

A very important note here. Your router can act as both a client and a server depending on which interface. On the WAN interface to the ISP it acts a client. On the LAN interface to your internal devices it acts as a server. These function are completely independent so be sure you do mix them up.

How DHCP works is the client sends out a broadcast and says IP want a IP address.

The server responds and gives the client a IP address as well as the amount of time it is allowed to keep the IP, ie the lease time.
The client at about 1./2 the lease time will send a new message to the server asking it if can keep using the IP. Three things can happen
The server says yes and the client updates the lease time
The server says no, which is not something that ever tends to happen, and the client immediately asks for new IP.
Something goes wrong and it gets no response. In this case depending on the implementation it will ask again in 1/2 the remaining time. It will only stop using the IP and ask for a new one when the time is completely up.

What is confusing on your post is you say you are changing the lease time. You can only change the lease time on the SERVER. This means you can only change the times on the LAN side of your router. It only control the times between the router and your end devices.
There is no way to change the lease times on the wan side this is fully in control of the ISP.

Most ISP set the lease time to multiple days if not weeks. The longer you set the lease time the more stable your network tends to be. The problem is if you set the lease time too high you might run out of IP addresses.
Something like a coffee shop where you have many different devices coming and going you need a short lease time. The number ISP customers that sign up for service or cancel service is not something that is changing quickly.

There is nothing you can change or set in your router to change the lease time the ISP equipment gives you. If you are actually losing the wan IP in less time than the lease is set for there is some other failure, like the internet actually going down, or there is some bug in the router firmware.

If you have a modem try plugging a PC directly into the modem without the router. You most times must power cycle the modem since it lock to the first mac address it sees. A PC you can actually use something like wireshark and capture the DHCP messages and see what is going on.
This may not be a quick way to find out things if it takes many hours to fail.

What is made this confusing is you talk able using a release/renew command to fix this. I have never seen a consumer grade router you could do this on. This is almost always a command people type on their computer.
 
May 1, 2022
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I am somewhat unclear as what IP address you are losing. DHCP does not function the way you describe.

A very important note here. Your router can act as both a client and a server depending on which interface. On the WAN interface to the ISP it acts a client. On the LAN interface to your internal devices it acts as a server. These function are completely independent so be sure you do mix them up.

How DHCP works is the client sends out a broadcast and says IP want a IP address.

The server responds and gives the client a IP address as well as the amount of time it is allowed to keep the IP, ie the lease time.
The client at about 1./2 the lease time will send a new message to the server asking it if can keep using the IP. Three things can happen
The server says yes and the client updates the lease time
The server says no, which is not something that ever tends to happen, and the client immediately asks for new IP.
Something goes wrong and it gets no response. In this case depending on the implementation it will ask again in 1/2 the remaining time. It will only stop using the IP and ask for a new one when the time is completely up.

What is confusing on your post is you say you are changing the lease time. You can only change the lease time on the SERVER. This means you can only change the times on the LAN side of your router. It only control the times between the router and your end devices.
There is no way to change the lease times on the wan side this is fully in control of the ISP.

Most ISP set the lease time to multiple days if not weeks. The longer you set the lease time the more stable your network tends to be. The problem is if you set the lease time too high you might run out of IP addresses.
Something like a coffee shop where you have many different devices coming and going you need a short lease time. The number ISP customers that sign up for service or cancel service is not something that is changing quickly.

There is nothing you can change or set in your router to change the lease time the ISP equipment gives you. If you are actually losing the wan IP in less time than the lease is set for there is some other failure, like the internet actually going down, or there is some bug in the router firmware.

If you have a modem try plugging a PC directly into the modem without the router. You most times must power cycle the modem since it lock to the first mac address it sees. A PC you can actually use something like wireshark and capture the DHCP messages and see what is going on.
This may not be a quick way to find out things if it takes many hours to fail.

What is made this confusing is you talk able using a release/renew command to fix this. I have never seen a consumer grade router you could do this on. This is almost always a command people type on their computer.
Hi,

Thanks for your response. I will try to be more clear. I just need time to look over some of the router's settings and perhaps reword some of my information. Regarding the connection and the release/renew, I can try to explain now.

In my wireless settings via the web interface, there is a subsection under "Network" for "DHCP Server" (this is where the ISP representative suggested I change the address lease time from its default value to a lower one).

Above this, also in "Network", is "Internet", and here I have listed my IP address, subnet mask, default gateway, primary and secondary DNSs. It is in this section that I can choose to click the button for "Release" and then I can "Renew". If I get an orange light on the router that indicates it no longer gets as signal from/connecting to the ISP, I must "Release" before I am able to "Renew." If I do this, it fixes the connectivity problem for some time.

I may have been confusing; the router doesn't have a release/renew button on its physical self--I do need to go into the settings on the web interface in order to do it. Although, it isn't necessary to type any kind of command. However, I can see that, as the heading suggests, I am only changing times for the server, or as you say, between my router and the devices.

The only submenu in which I can see anything related to "WAN" is in "Advanced Routing" under the main "Network" heading. In this window, I have three "Active Routes" in a "System Routing Table."

Again, thank you for your message, and I will try to look at some settings to be clearer on my information with my next reply.

To note, the ISP representative had told me they hadn't received any other complaints like mine recently, but I suppose it could still be a problem with the ISP. The firmware, I am not sure, as it started with whatever firmware version was in the router when I set it up, and it persisted with the upgrade of the firmware.

As of this morning, the router has been fine when I got up to check your reply; yesterday, I had to reset it again when I got up as it has lost connection to the ISP during the night.
 
It depends what kind of modem you have it might have messages in it. The router may also have a log but in general if it thinks the wan went down it will do a release/renew by itself.

What can happen is the internet drops between the modem and the ISP but since the port between the modem and the router is a simple ethernet cable that will stay up even when the internet is down.

A common IP used for a modem is 192.168.100.1. Put that in the web browser and see if you can find any interesting messages.

I guess it could be a defective router. If you think it does this every night maybe hook your pc up instead to the modem. Set the pc to not go into low power sleep mode. You could then look though the event logs for overnight and see if the pc detected any strange internet issues. This is purely so you do not blindly go buy a new router and it not be the problem.
 
May 1, 2022
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It depends what kind of modem you have it might have messages in it. The router may also have a log but in general if it thinks the wan went down it will do a release/renew by itself.

What can happen is the internet drops between the modem and the ISP but since the port between the modem and the router is a simple ethernet cable that will stay up even when the internet is down.

A common IP used for a modem is 192.168.100.1. Put that in the web browser and see if you can find any interesting messages.

I guess it could be a defective router. If you think it does this every night maybe hook your pc up instead to the modem. Set the pc to not go into low power sleep mode. You could then look though the event logs for overnight and see if the pc detected any strange internet issues. This is purely so you do not blindly go buy a new router and it not be the problem.
Hi, thanks so much for your response again. I'm about to leave for a few hours and will see how the router is when I get back. I will also remember to try checking out that IP address as well to see if it displays anything I might make sense of. I suppose it really could have just been a temporary ISP problem, but it seems strange that the rep did not see anything on their end when looking at the data. Some people with routers in this series report that the issue might clear up and reoccur after a few weeks too, at least from what I have read online.

Thanks again and I'll see what changes in a few hours.
 
May 1, 2022
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It depends what kind of modem you have it might have messages in it. The router may also have a log but in general if it thinks the wan went down it will do a release/renew by itself.

What can happen is the internet drops between the modem and the ISP but since the port between the modem and the router is a simple ethernet cable that will stay up even when the internet is down.

A common IP used for a modem is 192.168.100.1. Put that in the web browser and see if you can find any interesting messages.

I guess it could be a defective router. If you think it does this every night maybe hook your pc up instead to the modem. Set the pc to not go into low power sleep mode. You could then look though the event logs for overnight and see if the pc detected any strange internet issues. This is purely so you do not blindly go buy a new router and it not be the problem.
Hi again,

After being AFK today, the router appears to be working so far as it normally should before all this started Thursday. I'm hoping it stays that way, but I may have to come back after a few days. I certainly wish there was a good way to know what happened and why. It could have been an ISP issue, but I would have assumed the representative would have access to data on their end to confirm that. It's a bit strange.
 
Most level 1 tech are lucky if they can read their script to follow. It is not like the ISP pays these guys enough to have people with real training. Then again rebooting the router and the pc does fix the issue and so many end consumers are so technically illiterate they do not even know basic stuff like that.

Even if the level 1 tech would know what to look for they likely do not have access to things like logs or any advanced access to equipment. It is partially so a hacker can not social engineer the level 1 tech into something they shouldn't.

Not sure what you do, I was always lucky that since I worked in the field for many years I knew people I used to work with at many of the big ISP and could get them to help me talk to someone a normal end user could not.
 
May 1, 2022
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Most level 1 tech are lucky if they can read their script to follow. It is not like the ISP pays these guys enough to have people with real training. Then again rebooting the router and the pc does fix the issue and so many end consumers are so technically illiterate they do not even know basic stuff like that.

Even if the level 1 tech would know what to look for they likely do not have access to things like logs or any advanced access to equipment. It is partially so a hacker can not social engineer the level 1 tech into something they shouldn't.

Not sure what you do, I was always lucky that since I worked in the field for many years I knew people I used to work with at many of the big ISP and could get them to help me talk to someone a normal end user could not.
I'm just a lowly writer, although ironically, I do get clients from tech blogs who want me to write tech-based articles and how-tos for their sites. It's mostly basic stuff though, level 1 as you might say. I do have a brother-in-law who is extremely gifted with this kind of thing and can absorb coding books and other such stuff very easily--he's big into programming with a job to match it, but he's moving into upper management and I'm not still to this day not sure of all of his skills.

I'm the guy in my family that people think they can go to for "computer stuff," and he's the guy in the family they should actually go to.
 

gggplaya

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If you didn't change any settings and the firmware didn't update overnight. I'm leaning towards a hardware failure. If it becomes more frequent(less time between failures) then it for sure is a hardware failure.

If it updated overnight, then it could be a software bug. I have no faith in TP-LINK firmware. Using aftermarket firmware like DDWRT or FreshTomatoe are better options.

What kind of modem do you have?
 
May 1, 2022
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If you didn't change any settings and the firmware didn't update overnight. I'm leaning towards a hardware failure. If it becomes more frequent(less time between failures) then it for sure is a hardware failure.

If it updated overnight, then it could be a software bug. I have no faith in TP-LINK firmware. Using aftermarket firmware like DDWRT or FreshTomatoe are better options.

What kind of modem do you have?
Hi, thanks for your response.

I spoke too soon yesterday, as the problem has reoccurred today a couple of times. I'd love for it just to be a firmware issue, but I am not sure if there is a way to check if it did a stealth update? There was an update waiting when I did go to check Friday, which would have been after the failure started Thursday. I did do that, but the problem persisted. I haven't rolled it back yet and didn't consider that it could have updated on its own. I do have some logs information in the system tools for the router, but they don't seem to indicate any kind of error message (but then, I am no expert).

My modem was provided by my ISP, and I will try to read the info off the front plate tomorrow. I'd be happy to do it tonight, but they installed it in a place that is pretty hard for me to crawl to, I am embarrassed to admit, and it takes a lot of effort for me to get in and out of that space. For a regular person it wouldn't be a big deal, but I've got a few mobility issues due to palsy.

I have called the ISP 3 times over the weekend asking for different information and fixes, and they do look at the modem each time and, according to them, it is in good shape with excellent signals/speeds (it is true that I don't need to mess with the modem when the router goes offline, I just need to do the renew/refresh.

I will say that I did crawl around under there a bit today to plug in the ethernet directly to the modem, and that didn't seem to help, as I get an "Ethernet does not have a valid IP" error when I want to bypass the router that way. I just wanted to check if it was just the router only. I don't think there's a real problem with the modem, but doing an IPconfig refresh and renew on my computer didn't help with that, or did restarting the computer or modem. I was hoping it would just connect when I hooked it up, but alas, looks like I may need to crawl around under there again tomorrow.

The modem isn't quite as new as the router but it is pretty new. It came with a mandatory fiber upgrade my ISP did last year. They put everything in, and I kinda wish I'd been given a choice where they could've up the modem in a spot that was a little easier to access for me, but oh well.

EDIT: Nevermind, the router lost connection again as I was writing this reply, right on time, so I took the opportunity to crawl under there again. There is a sticker on the front of the modem with a barcode, but there is otherwise no identifying information that I could see on the front panel. I guess I could just call up my ISP again and ask them what tech they provide..

Again, thanks for your response.

Further Edit: Based on my observations, it's pretty much losing that ISP connection at the 5-hour mark like clockwork. I'll check tonight, but it should do it again around 11:13 local time at night. Should I just roll back the firmware a couple of versions? I'm prepared to just buy a new router, but it is so weird that, aside from yesterday where it had no problems, it loses connection to the ISP at the exact same intervals. Every time. LAN stays up (my phone can still connect to the network and access the router's webpage, etc).
 
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It is looking like it is the router. Modems are pretty strange sometimes. They lock the first mac address they see for some reason. What makes this strange is the ISP not the modem gives the mac address an IP address. I assume it is some security thing but they don't actually care what the mac is. You just power cycle the modem
and it will then take a different mac, as long as it is the first to connect.

You could also go into the ethernet setting on your pc and key in the mac address of the router wan port. Spoofing it is that trivial so I am unsure why the restriction in the modem.
 
May 1, 2022
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It is looking like it is the router. Modems are pretty strange sometimes. They lock the first mac address they see for some reason. What makes this strange is the ISP not the modem gives the mac address an IP address. I assume it is some security thing but they don't actually care what the mac is. You just power cycle the modem
and it will then take a different mac, as long as it is the first to connect.

You could also go into the ethernet setting on your pc and key in the mac address of the router wan port. Spoofing it is that trivial so I am unsure why the restriction in the modem.
Hi Bill,

Thanks once again for your continued assistance. Out of all the simple things I've tried, I did not yet power cycle the modem. Reason being, I have to awkwardly get on my stomach and hold on the front faceplate of the thing while I unplug it, otherwise the plate comes off when I try to do that, and it can be a hassle to get back on while I'm in that awkward position. But, I decided to try that tonight anyway, and I power cycled the router along with it for good measure, although I'd done that already since it is nearby but much easier to access.

Perhaps it will have some effect. I'll also see if the power cycle could've helped me finally bypass the router if necessary, and I'll look into keying the router wan port. I'd prefer that to getting down there again.

I guess it is also time to ask the person who gifted me the router over the holidays to open a ticket to see about making a return and replacement, just to at least see what the retailer says in case we need to do that.
 
May 1, 2022
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Wait, will the owner still be using their own router, while you use yours?

That's not a good idea, because you're be double NAT'd. Some games won't like that.
Hi Playa,

Thanks for your reply.

I apologize, but I'm a bit confused by your question. There's just one router here and one owner (me), but the router I've been using since the beginning of the year is a new one that was gifted to me. I may have said something confusing in one of my earlier replies. If so, sorry about that.

The router did lose another connection a bit sooner than it usually does, so I guess it is pointing toward some hardware fault. I will add that, so far, I haven't done anything with MAC cloning, rolling back the firmware, or doing anything that involved changing "flood values in the DoS section of the router's settings," which are all things some other people said worked for them. In fact, that particular function on my router isn't enabled by default. Some people also mentioned "getting IP Using Unicast DHCP (Usually not required") also fixed things for them, but I haven't tried that. I'm loathe to mess with any settings that I don't fully "get."

Just kinda throwing out there solutions or partial answers I keep coming across but haven't tried yet, not sure if any of it would work.

Once again, thanks for all the help, guys.
 

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