HardwareBanter - View Single Post - Mysterious internet/ethernet issue (kinda need testing/connection/communicationservice to diagnose it ???)

**[email protected]** · October 12th 18, 07:34 PM posted to alt.comp.hardware.pc-homebuilt

On Friday, October 12, 2018 at 8:04:51 PM UTC+2, Char Jackson wrote:
On Fri, 12 Oct 2018 08:55:31 -0700 (PDT), wrote:

I tried:

192.168.100.2 for windows PC
255.255.255.0 netmask.

The cable modem remains unaccessable from the local LAN.

Assuming you were still physically connected directly to the modem
device, that tells me one of two things:
1. The modem may not have a web server at all. Not all plain DOCSIS
modems do, although most do.
2. Or, your modem may be a combo modem-router, which I believe is likely
to be the case. As a result, there will not be a web server listening at
the usual 192.168.100.1 address because:
2A: the modem info is available via the router interface, or
2B: the ISP doesn't make the modem info available to you.

So your knowledge of this is now completely useless, because of either:

1. It's locked by the ISP, these cable modems can only be accessed from the outside.

2. It's a bug/problem, modem was resetted.

Most likely cause is locking/updating of the cable modem bios/firmware.

There was a thread on the internet about people locating their public IPs of their cable modems, this is more difficult to do then it seems.

It's difficult because cable modems don't have public IP addresses, at
least not a public address that you can access (if the ISP is doing
their job properly). A plain DOCSIS modem will usually have a web server
at 192.168.100.1 that is only accessible from the LAN side of the modem,
(you can access it, but the ISP cannot), and a web server that is only
accessible from the WAN side of the modem (the ISP can access it, but
you cannot). Technically, the WAN IP is a publicly routable IP, but if
the ISP is even slightly competent, you should not be able to access
your modem via that IP. You'd have to traverse multiple firewalls that
are internal to the ISP.

A tracert will probably not report it because the cable modem does not take part in the trace and does not reveal itself ? Or there is another reason for it.

At the networking level, a plain cable modem is technically a bridge,
and bridges don't operate at OSI Layer 3 where traceroutes operate.
That's why cable modems don't show up in a traceroute. However, it
appears that you don't have a plain cable modem, but a combo
modem-router unit. As such, it (the router portion of that combo device)
should appear in your traceroute results. The modem portion will not
show up because of the reason given above.

If you know how to find my public IP address of my Cable modem I am all ears, cause this is interesting stuff.

And apperently it is something completely different than my Windows PC public IP address which I can tell you right now is simply:

85.25.113.203

mask

255.255.254.0

gateway

84.25.112.1

I assume that's a typo. The gateway should be 85.25.112.1

Well spotted, but it's other way around at least currently.

85 was the typo, this must be 84 for my public ip address

dhcp

10.255.235.1

If that's the IP address of your PC, then yes, you're using NAT. By
definition, addresses within the 10.x.x.x range are not publicly
routable.

No this is ip dhcp gateway... just to lazy to type it follow.

See windows 7 network/adapter screenshot

On second thought just gonna roll out some ipconfig at least this can be copied pasted somewhat... even from ****ty ms-dos prompt

this will get an update in windows 10 sometime