Non-functional access to the cable modem administration interface

Non-functional access to the cable modem administration interface

Non-functional access to the cable modem administration interface
Non-functional access to the cable modem administration interface
2024-07-20 10:17:56 - last edited 2024-07-20 18:12:03
Model: Archer AX73  
Hardware Version: V1
Firmware Version: 1.3.6

Hey. Hey,

 

I have an interesting problem with my Vodafone router and modem. Specifically - TP-Link AX73 router and Vodafone Station modem. The modem is in bridge mode, the public IP is set up on the router. The modem itself has a management IP of 192.168.100.1.

 

I don't understand the reason, but I'm having trouble getting to this IP. Traceroute to this IP is without problem (both directly from the router's diagnostic page and from the computer behind it). However, the ping is not responding, and the HTTP/S requests are also timeouting.

If I turn off the modem (unplug it) and turn it back on, everything works for a while, about one minute. Then the connection starts refusing again and access doesn't work (internet yes, but modem administration no).

 

It doesn't matter if the SPI Firewall is on or off, it doesn't matter if I create the route manually (192.168.100.0/24 over the WAN) or not at all (all unknown ranges go automatically over the WAN). But it is interesting that as soon as I create a route, it pings with the modem and access to it starts working (again, for a minute or so) and stops again. As soon as I delete the route, the situation repeats. 

 

It's like something in the background is actively blocking access to this range through the WAN interface (something like BCP38?).

Has anyone encountered this condition? DOCSIS (3.1) from Vodafone CZ.

 

 

C:\Users\Petr>ping 192.168.100.1 -t

Pinging 192.168.100.1 with 32 bytes of data:
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
--> route to 192.168.100.0 subnet created ...
Reply from 192.168.0.1: Destination net unreachable.
Reply from 192.168.0.1: Destination net unreachable.
Request timed out.
Reply from 192.168.100.1: bytes=32 time=1ms TTL=63
Reply from 192.168.100.1: bytes=32 time=2ms TTL=63
Reply from 192.168.100.1: bytes=32 time=30ms TTL=63
Reply from 192.168.100.1: bytes=32 time=2ms TTL=63
Reply from 192.168.100.1: bytes=32 time<1ms TTL=63
Reply from 192.168.100.1: bytes=32 time=28ms TTL=63
Reply from 192.168.100.1: bytes=32 time=2ms TTL=63
Reply from 192.168.100.1: bytes=32 time=3ms TTL=63
Reply from 192.168.100.1: bytes=32 time=2ms TTL=63

... and again ...
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.

--> route deleted ...
Reply from 192.168.0.1: Destination net unreachable.
Reply from 192.168.0.1: Destination net unreachable.
Request timed out.
Request timed out.
Reply from 192.168.100.1: bytes=32 time=10ms TTL=63
Reply from 192.168.100.1: bytes=32 time=14ms TTL=63
Reply from 192.168.100.1: bytes=32 time=1ms TTL=63
Reply from 192.168.100.1: bytes=32 time=1ms TTL=63
Reply from 192.168.100.1: bytes=32 time=1ms TTL=63
Reply from 192.168.100.1: bytes=32 time=7ms TTL=63
Reply from 192.168.100.1: bytes=32 time=1ms TTL=63
Reply from 192.168.100.1: bytes=32 time=1ms TTL=63
Reply from 192.168.100.1: bytes=32 time=2ms TTL=63

... and again (no response) ...
Request timed out.
Request timed out.
... (10x)
Request timed out.
Request timed out.

... and all of a sudden, the approach is back on...
Reply from 192.168.100.1: bytes=32 time=1ms TTL=63
Reply from 192.168.100.1: bytes=32 time=2ms TTL=63
Reply from 192.168.100.1: bytes=32 time=2ms TTL=63
Reply from 192.168.100.1: bytes=32 time<1ms TTL=63
Reply from 192.168.100.1: bytes=32 time=1ms TTL=63
Reply from 192.168.100.1: bytes=32 time=1ms TTL=63
Reply from 192.168.100.1: bytes=32 time=1ms TTL=63
Reply from 192.168.100.1: bytes=32 time=2ms TTL=63
Reply from 192.168.100.1: bytes=32 time=1ms TTL=63
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Reply from 192.168.100.1: bytes=32 time=1999ms TTL=63
Reply from 192.168.100.1: bytes=32 time<1ms TTL=63
Reply from 192.168.100.1: bytes=32 time=2ms TTL=63
Reply from 192.168.100.1: bytes=32 time=2ms TTL=63
... (50x)
Reply from 192.168.100.1: bytes=32 time=1ms TTL=63
Reply from 192.168.100.1: bytes=32 time=1ms TTL=63
Request timed out.
... (20x)
Request timed out.
Reply from 192.168.100.1: bytes=32 time=1ms TTL=63
Reply from 192.168.100.1: bytes=32 time=20ms TTL=63
... (50x)
Reply from 192.168.100.1: bytes=32 time=2ms TTL=63
Reply from 192.168.100.1: bytes=32 time=2ms TTL=63
Reply from 192.168.100.1: bytes=32 time=1ms TTL=63
Request timed out.
... (20x)
Request timed out.

Ping statistics for 192.168.100.1:
    Packets: Sent = 440, Received = 199, Lost = 241 (54% loss),
Approximate round trip times in milli-seconds:
    Minimum = 0ms, Maximum = 1999ms, Average = 12ms
Control-C

^C

  0      
  0      
#1
Options
2 Reply
Re:Non-functional access to the cable modem administration interface
2024-07-20 14:00:42

  @Petr89 

 

Hi,

 

In my experience, this behavior is not too unusual.

 

Normally, a modem that is set to bridge mode should be accessed by connecting a computer directly to the modem via Ethernet cable. Since the modem in bridge would try to assign a public IP address to the connected device, the computer's network card needs to be manually set to an unused IP address in the router's local subnet.

 

For example, in your case set the IP address of the computer to 192.168.100.2, then connect it via Ethernet cable to the modem and then you should be able to browse to the modem's management GUI via the IP address 192.168.100.1.
 

  0  
  0  
#2
Options
Re:Non-functional access to the cable modem administration interface
2024-07-20 18:08:11 - last edited 2024-07-20 18:15:33

  @woozle 

This solution works, of course, and it's the only way I can get to the modem, but not really. When I connect my PC directly to the modem, I get a dynamic public IP (range 81.XXX.XXX.XXX) and access to the modem IP (192.168.100.1) works normally. 

 

When I use, for example, a Mikrotik instead of my current router (AX73), access to the modem administration works fine. So the fault must be in the router itself, not in the modem or the IP address solution.

 

The 192.168.100.X/24 range is the range outside the router, or it is directed outside, via WAN/GW and this solution should work (it works for everyone). Not for me though, because there will be a bug somewhere in the router's FW (probably).

 

How else to explain the behavior where after adding a route/path, access works for a while, then stops, then maybe starts again (for a while) and then doesn't work until the route is removed. Once I delete the route/path again, access works for a few seconds, then stops and I can't access it anymore.

 

EDIT: 

So the fault is really in the modem, not in the router. I'm closing the thread :-) thanks for the advice.

Detail - https://t.ly/ELLur

  0  
  0  
#3
Options