Question Internet drops like 2-3 times a day because of public ip change

Ryunosei

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Hello, as title says my connection drops very often because of ip changes. I don't know if this is related to my ISP or a bad configuration in my router.
My LAN is as follows:
ISP Router in Bridge Mode.
My Router connected to ISP Router.
Phones, Tablets, etc. connected via wifi.
PCs connected using static ip outside of DHCP's range.




As you can see there is a ip renew very often.
Sometimes I saw that a log like that one but with the ips being the same in both cases like:
(Numbers are an example to see which ips are the same)
  1. Whole process from "entering released state" to "dynamic IP obtained an IP successfully"
  2. DHCPC Unicasting a release of 190.160.0.3 to 200.50.31.6
After a few minutes...
  1. Whole process from "entering released state" to "dynamic IP obtained an IP successfully"
  2. DHCPC Unicasting a release of 190.160.0.3 to 200.50.31.6
Is there a problem with my configuration? Or is my ISP changing my ip all the time?
Thanks in advance
 
It almost acts like there is a second dhcp server ? I don't know where it is getting those 2 ip addresses from. The DHCP requests are using 200.114.150.202 for your router and 172.20.2.71 for the dhcp server. The ip addresses are in hex.

What is strange about 172.20.2.71 is it is a private ip addresses.

There is really nothing you can do on your router if it must run via dhcp. The ISP is in full control of this and your router takes what it gets. This almost looks like someone accidentally(?) hook up a router backwards and the ISP did not block dhcp requests.

You could try hooking your PC up instead of the router and see what it gets for dhcp messages. Wireshark will let you want the messages.

Maybe ask the ISP what the DHCP server address should be that way you know if your machine is talking to the proper device
 

Ryunosei

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It almost acts like there is a second dhcp server ? I don't know where it is getting those 2 ip addresses from. The DHCP requests are using 200.114.150.202 for your router and 172.20.2.71 for the dhcp server. The ip addresses are in hex.

What is strange about 172.20.2.71 is it is a private ip addresses.

There is really nothing you can do on your router if it must run via dhcp. The ISP is in full control of this and your router takes what it gets. This almost looks like someone accidentally(?) hook up a router backwards and the ISP did not block dhcp requests.

You could try hooking your PC up instead of the router and see what it gets for dhcp messages. Wireshark will let you want the messages.

Maybe ask the ISP what the DHCP server address should be that way you know if your machine is talking to the proper device
ISP's router is in bridge mode, dhcp disabled, nat disabled, wifi disabled.
My Router is the only one with DHCP enabled as far as I know.
 

Ryunosei

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Last logs:

8May 1 07:37:30DHCPNOTICEDHCPC Unicasting a release of 200.114.150.202 to 172.20.2.113
55May 1 09:34:11DHCPNOTICEDHCPC Unicasting a release of 200.114.150.202 to 172.20.2.113
76May 1 10:21:01DHCPNOTICEDHCPC Unicasting a release of 200.114.150.202 to 172.20.2.113
97May 1 10:44:36DHCPNOTICEDHCPC Unicasting a release of 181.170.19.10 to 172.20.2.113
So it seems that it released the same ip 3 times then it changed. Can 172.20.2.113 be the ISP's router?
 

Ryunosei

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@bill001g is referring to the WAN side of your personal router. Multiple DHCP servers fighting on the WAN side of your router.
So this means that my ISP is causing the problem?

@EDIT: I would like to test it connecting my pc directly to my ISP's router but I don't know how. I disconnected my router, connected my pc to port 1 (same port I used for the router) and let windows configure by itself, but I get no connection. It says "Wrong adapter configuration", since my IP is dynamic idk which ip I should write in my adapter's configuration
 
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Ryunosei

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Also, I notice that you said the modem is "bridged out" which is usually done if you are assigned a static ip. If this is so, you MUST use the dns servers assigned so it will route correctly, otherwise it will reset periodically when the isp scans the mac adresses on the system and doesn't get the correct routing from your modem.

But either way, the internal lan and subnet must be different than the WAN side.
I have a dynamic IP and set dynamic on my router's configuration
 
Your ISP is not using 8.8.8.8 but you are over riding them on YOUR DHCP setting you give to your end clients. That really is all that matters for DNS. You can see the DNS servers in the dhcp log you had again in hex. One of the IP is 200.42.04.204 and I am too lazy to do the other.

DNS is not the issue since your end device will always use 8.8.8.8.

Your issue is your WAN port is dropping because you get strange DHCP stuff. The only option your router has is to accept DHCP information or not. Be nice if you had the option of using a static ip.

I guess you could try the upgrade to the latest firmware and see if it makes a difference. If your router is on the list of supported devices I suppose you could try dd-wrt or one of the other third party firmwares. If it was a bug in the DHCP in the code that would eliminate that.

Still I can see no reason you are getting these messages. You are getting a valid dhcp lease that is good for almost a 24hours so this stuff should not be happening.
 
The problem is that they don't care about my router. Their answer was "if you have a problem with your router, it might be the router". They didn't even hear what I said.
If the IP renews that often and you're sure this is the source of your issue. Then configure a device directly into their modem and prove it's on the ISP's end. Take your router out of the equation.
 

Ryunosei

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Your ISP is not using 8.8.8.8 but you are over riding them on YOUR DHCP setting you give to your end clients. That really is all that matters for DNS. You can see the DNS servers in the dhcp log you had again in hex. One of the IP is 200.42.04.204 and I am too lazy to do the other.

DNS is not the issue since your end device will always use 8.8.8.8.

Your issue is your WAN port is dropping because you get strange DHCP stuff. The only option your router has is to accept DHCP information or not. Be nice if you had the option of using a static ip.

I guess you could try the upgrade to the latest firmware and see if it makes a difference. If your router is on the list of supported devices I suppose you could try dd-wrt or one of the other third party firmwares. If it was a bug in the DHCP in the code that would eliminate that.

Still I can see no reason you are getting these messages. You are getting a valid dhcp lease that is good for almost a 24hours so this stuff should not be happening.
Oh nono, I meant that google's primary DNS is 8.8.8.8 :D. About my ISP's DNS everytime I call they say they don't know the DNS that's why I use google's DNS hahaah.
The latest firmware has a bug that breaks bandwidth control so I can't update. About dhcp lease, it was 60 minutes when I took the screenshot (it says 1440 but a reboot is required for it to take effect)

If the IP renews that often and you're sure this is the source of your issue. Then configure a device directly into their modem and prove it's on the ISP's end. Take your router out of the equation.
Yep, I will try that. I didn't because I couldn't connect directly to my ISP's router. Will see if the ipconfig /release /renew works

@EDIT: Forgot to say, thank you all for helping me
 
Oh nono, I meant that google's primary DNS is 8.8.8.8 :D. About my ISP's DNS everytime I call they say they don't know the DNS that's why I use google's DNS hahaah.
The latest firmware has a bug that breaks bandwidth control so I can't update. About dhcp lease, it was 60 minutes when I took the screenshot (it says 1440 but a reboot is required for it to take effect)


Yep, I will try that. I didn't because I couldn't connect directly to my ISP's router. Will see if the ipconfig /release /renew works

@EDIT: Forgot to say, thank you all for helping me
Your ISP will assist you with configuring your PC/Laptop directly into your ISP's router.
 
I would like to test it connecting my pc directly to my ISP's router but I don't know how.
If you've set your ISP router in "Bridge" mode, it means that it is acting as a modem, and you should set up your PC in the same way your own (secondary) router is set. You might have to add PPoE connection to your PC, with correct (ISP-specific) user name / password.

And once you start experimenting with ISP router: How is your network behaving when using only it?
 
"About dhcp lease, it was 60 minutes when I took the screenshot (it says 1440 but a reboot is required for it to take effect)"

Again you are looking at the wrong DHCP. You are looking at the lease your router provides to your end clients not the lease the ISP provides to your router. The number you see is 18765 which I am not sure is minutes or seconds.
 

Ryunosei

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Your ISP will assist you with configuring your PC/Laptop directly into your ISP's router.
Actually, no. When I called they said it was my computer's fault that it couldn't connect to the router. When I asked for ip and dns they said they don't know.

If you've set your ISP router in "Bridge" mode, it means that it is acting as a modem, and you should set up your PC in the same way your own (secondary) router is set. You might have to add PPoE connection to your PC, with correct (ISP-specific) user name / password.

And once you start experimenting with ISP router: How is your network behaving when using only it?
What user and password you mean? Where should I input those values?

"About dhcp lease, it was 60 minutes when I took the screenshot (it says 1440 but a reboot is required for it to take effect)"

Again you are looking at the wrong DHCP. You are looking at the lease your router provides to your end clients not the lease the ISP provides to your router. The number you see is 18765 which I am not sure is minutes or seconds.
Oh, where did you get that number from?

Thanks for all the answers.
 
Actually, no. When I called they said it was my computer's fault that it couldn't connect to the router. When I asked for ip and dns they said they don't know.


What user and password you mean? Where should I input those values?


Oh, where did you get that number from?

Thanks for all the answers.
Why would they say your computer is at fault when you only asked for assistance configuring your computer to connect directly to your modem? Ask to speak to a manager.
 

davesnothere

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But something tells me you are not having any issues. The isp may have software in place that if it detects a web server on a dynamic host connection it may reset the ip address for security reasons. It would not effect you unless you are trying to do web hosting on a consumer class connection.
 

davesnothere

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Last logs:


8May 1 07:37:30DHCPNOTICEDHCPC Unicasting a release of 200.114.150.202 to 172.20.2.113


55May 1 09:34:11DHCPNOTICEDHCPC Unicasting a release of 200.114.150.202 to 172.20.2.113


76May 1 10:21:01DHCPNOTICEDHCPC Unicasting a release of 200.114.150.202 to 172.20.2.113


97May 1 10:44:36DHCPNOTICEDHCPC Unicasting a release of 181.170.19.10 to 172.20.2.113

So it seems that it released the same ip 3 times then it changed. Can 172.20.2.113 be the ISP's router?
no, because you have your subnet on the same subnet as the isp node, and the upstream DHCP server is calling for the ip address range of 181.170.19.10 to 172.20.2.113 to reset. So since you are on the same subnet, it resets your ip address on your network too. Changing the internal network to a better ip range with a different subnet is the solution as the resets on the modem side would not effect your network.

Is this why you assigned a static ip to your computer? Usually that is done mostly for nas or printers to have static connections.
 
no, because you have your subnet on the same subnet as the isp node, and the upstream DHCP server is calling for the ip address range of 181.170.19.10 to 172.20.2.113 to reset. So since you are on the same subnet, it resets your ip address on your network too. Changing the internal network to a better ip range with a different subnet is the solution as the resets on the modem side would not effect your network.

Is this why you assigned a static ip to your computer? Usually that is done mostly for nas or printers to have static connections.
He doesn't have the lan on the same subnet his lan is on 192.168.1.x. The release message is not being caused by a reset from the server. It appear the router is just sending the release and that is they key question here. Why is his router sending these release messages. There is nothing in the log you just see it send the release and then go though the process of requesting a new reservation for the same ip address he just released.

The other thing I noticed after looking at this again the these release messages are being sent at about 23 minutes apart or multiples of 23 minutes.

I suspect plugging a pc directly into the modem maybe very informative since there are likely different log messages and the dhcp traffic can be directly captured with wireshark. I am starting to suspect a bug in the router firmware but there is not enough information. Key to find out is what makes the router send these release messages.
 

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