Default Gateway no longer accessible

[Sebastian42]

A TP-Link modem [MODEL TD-W8901G] used to give me access to what ipconfig in CMD says is its default gateway : 192.168.1.1 After years of use it would no longer accept credentials of admin/admin. Now it will no longer give access to 192.168.1.1 - it times out - and does that in 7 different browsers.
My ISP examined the issue and recommended a new modem. That new modem (D-Link) would not accept those credentials either; and also no longer allows access to 192.168.1.1 The ISP then recommended a second new modem - same model D-Link. It would not even let me reach 192.168.1.1
My internet is quite good most of the time, so that is not an issue. There are rare times when the internet is missing - and THEN I look around at what I can tweak to get it back, but I have no access to 192.168.1.1 The problem is the same on my laptop - connected through WiFi.
My ethernet-connected desktop is an upgrade of Win7 Ultimate 32bit to Win10 v1511; my laptop is a fresh install of Win10 v1607 - also 32bit

[deanwebb]

It is possible that the wifi modem does not use 192.168.1.1 as the administration address. I have had modems that used other addresses, like 192.168.1.254, among others.

This would be a good time to check the documentation on that modem.

[vikramj5555]

A TP-Link modem [MODEL TD-W8901G] used to give me access to what ipconfig in CMD says is its default gateway : 192.168.1.1 After years of use it would no longer accept credentials of admin/admin. Now it will no longer give access to 192.168.1.1 - it times out - and does that in 7 different browsers.
My ISP examined the issue and recommended a new modem. That new modem (D-Link) would not accept those credentials either; and also no longer allows access to 192.168.1.1 The ISP then recommended a second new modem - same model D-Link. It would not even let me reach 192.168.1.1
My internet is quite good most of the time, so that is not an issue. There are rare times when the internet is missing - and THEN I look around at what I can tweak to get it back, but I have no access to 192.168.1.1 The problem is the same on my laptop - connected through WiFi.
My ethernet-connected desktop is an upgrade of Win7 Ultimate 32bit to Win10 v1511; my laptop is a fresh install of Win10 v1607 - also 32bit

Use this below given solution -

Step 1
Click Start->Run, type cmd and press Enter.

Step 2
Type ipconfig /release at the prompt window, press Enter, it will release the current IP configuration.

Step 3
Type ipconfig /renew at the prompt window, press Enter, wait for a while, the DHCP server will assign a new IP address for your computer.

Sent from my SM-G7102 using Tapatalk

[Sebastian42]

Vikram - no improvement.

Deanweb - The 'DOS' window resulting from Vikrams' suggestion states that Default Gateway is 192.168.1.1 - isn't that enough proof ?

[icecream-guy]

host firewall blocking?

can you ping 192.168.1.1?
is the mac address in your arp table?

another way to find unknown ip's is to ping 255.255.255.255
then check the arp table on the pc.

[Sebastian42]

I don't understand your instructions, so without detailed steps, can not follow them.

NEW INFORMATION :
I've connected the newest modem to a PC different from this - and all is well - default gateway accessible; credentials accepted.

Then I connected THIS PC to that new modem, and could not access the internet, so I reconnected THIS PC to the old modem, and am able to make this reply.

[deanwebb]

OK, so both modems work.

On each PC, do Start-Run-CMD and in the command window, run "Ipconfig /all" and collect all the results for the interface that is used for internet connectivity.

Compare those results, especially for the default gateway.

Next, check the documentation of each modem to see what the IP address for modem administration is. It is possible that the admin address is NOT the address of the default gateway, or may be on a specialized port. You will need the vendor information in order to access the admin interface of the modem.