Discussion:
Cable Modem Problem(?)
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jimrx4
2017-06-01 21:20:56 UTC
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I recently purchased a new cable modem - Motorola MB7420 - and with my
Windows-10 system I went merrily along. I also have an image of Windows-7
which I use sometimes when I want to play certain games. When I install the
Win-7 image I'm having a problem(?) connecting to the Internet. It take 2 to
3 minutes (I timed it) for the internet to be recognized. The connection
icon (on lower right) -when rebooting - has the revolving blue circle and
then a red x overlays the icon. When I put the mouse pointer over the red X
and right-click I get the small window that asks "Troubleshoot... and Open
Network & sharing..." When I open the Network & sharing windows, Windows-7
automatically tries to correct the connection problem which it finally does.
Any ideas what's wrong or why it take 2-3 minutes for Win-7 to finally make
the connection? Windows-10, zip-zap, no problems whatsoever.
Paul
2017-06-01 23:50:54 UTC
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Post by jimrx4
I recently purchased a new cable modem - Motorola MB7420 - and with my
Windows-10 system I went merrily along. I also have an image of
Windows-7 which I use sometimes when I want to play certain games. When
I install the Win-7 image I'm having a problem(?) connecting to the
Internet. It take 2 to 3 minutes (I timed it) for the internet to be
recognized. The connection icon (on lower right) -when rebooting - has
the revolving blue circle and then a red x overlays the icon. When I put
the mouse pointer over the red X and right-click I get the small window
that asks "Troubleshoot... and Open Network & sharing..." When I open
the Network & sharing windows, Windows-7 automatically tries to correct
the connection problem which it finally does. Any ideas what's wrong or
why it take 2-3 minutes for Win-7 to finally make the connection?
Windows-10, zip-zap, no problems whatsoever.
The Windows networking interface carries out a pretty simple test.
Microsoft has a server on the network, that the network interfaces
use for test purposes. The address is symbolic, so first the test
tries to do a DNS lookup. Next, the teeny-tiny file on the server
is fetched as a test. The file only contains a couple words, which
the test uses as verification that the network interface is good.
You might see the blue circle until that sequence is completed.

This might mean, on a typical day, the Microsoft gets to "see"
500 million computers boot. Since minimal info is exchanged, this
is not your usual pushy telemetry. It's just a simple kind of
ping-like test. And allows the desktop to put up the "healthy
network" icon.

The troubleshooter can reset the networking stack, using the
two popular "netsh" commands you see mentioned in this group
occasionally.

The router may be having a problem getting the details
from the ISP. The ISP runs a DHCP server. On request from the
router, it gives the router an IP address, and it gives the
router two DNS server addresses to access. In turn, the
router has its own DHCP server, and it serves local addresses
like 192.168.0.1 to your LAN machine.

This all assumed the cable modem does the following

/----- combo box --------\

DOCSIS WAN LAN
<Cable>------ modem ------ router ----
----
----
----

The WAN side uses the public ISP IP address. The LAN side
uses the private IP addresses dished out by DHCP running
on the router.

If you "bridge" the cable modem, the router is disabled...
Similarly, if you had an older unit, it might just be
a modem. The output of bridged things, can be PPPOE,
and then a username/password is required to "log into"
the ISP. Windows 7 can sniff this situation, and it
will use its PPPOE termination stack. Seeing a public
address in "ipconfig", would confirm the usage of PPPOE
(like if someone else set it up and you were "just a victim").

DOCSIS
<Cable>------ modem ------ <PPPOE> --- Win7 terminates PPPOE
Machine has a *public*
address, outside the
192.168.x.x or 10.x.x.x
range.

I expect your cable modem, is a combo modem/router, running
in "normal mode", and the first diagram applies.

*******

Note that some network failures, are the result of subsystems
in the OS. For example, the networking stack uses .NET libraries.
(The similarity of names there is purely coincidental.)

Some executables need "runtime compilation" after a .NET update.
On WinXP, the firewall in particular, can foul up after a .NET
update and there is an "ngen" command to force the .NET assemblies
to be recompiled. This can take around ten minutes, to do all the
system executables which have .NET dependencies. This isn't likely
to be the reason on Win7 (it doesn't have this "ngen bug"), but I
mention the subsystems as potential culprits. (There can be a
pregnant pause until this baloney is finished in the background.)
In addition, malware that upsets certain networking stack settings,
could also be responsible for fouling up the connection, and then the
"netsh" commands the Troubleshooter uses, kinda sorta makes it
work again.

You could be connecting via IPV4 or IPV6. I'm IPV4-only here, so I
cannot comment on the early morning dynamics of IPV6 coming up
on a broadband device. I presume Microsoft still does the same
"basic networking test" for the "healthy network" icon to show.

Paul
jimrx4
2017-06-02 00:13:20 UTC
Permalink
Raw Message
Wow. Thanks for the info. Now I need time to digest this.
I appreciate your response.
Post by jimrx4
I recently purchased a new cable modem - Motorola MB7420 - and with my
Windows-10 system I went merrily along. I also have an image of
Windows-7 which I use sometimes when I want to play certain games. When
I install the Win-7 image I'm having a problem(?) connecting to the
Internet. It take 2 to 3 minutes (I timed it) for the internet to be
recognized. The connection icon (on lower right) -when rebooting - has
the revolving blue circle and then a red x overlays the icon. When I put
the mouse pointer over the red X and right-click I get the small window
that asks "Troubleshoot... and Open Network & sharing..." When I open
the Network & sharing windows, Windows-7 automatically tries to correct
the connection problem which it finally does. Any ideas what's wrong or
why it take 2-3 minutes for Win-7 to finally make the connection?
Windows-10, zip-zap, no problems whatsoever.
The Windows networking interface carries out a pretty simple test.
Microsoft has a server on the network, that the network interfaces
use for test purposes. The address is symbolic, so first the test
tries to do a DNS lookup. Next, the teeny-tiny file on the server
is fetched as a test. The file only contains a couple words, which
the test uses as verification that the network interface is good.
You might see the blue circle until that sequence is completed.

This might mean, on a typical day, the Microsoft gets to "see"
500 million computers boot. Since minimal info is exchanged, this
is not your usual pushy telemetry. It's just a simple kind of
ping-like test. And allows the desktop to put up the "healthy
network" icon.

The troubleshooter can reset the networking stack, using the
two popular "netsh" commands you see mentioned in this group
occasionally.

The router may be having a problem getting the details
from the ISP. The ISP runs a DHCP server. On request from the
router, it gives the router an IP address, and it gives the
router two DNS server addresses to access. In turn, the
router has its own DHCP server, and it serves local addresses
like 192.168.0.1 to your LAN machine.

This all assumed the cable modem does the following

/----- combo box --------\

DOCSIS WAN LAN
<Cable>------ modem ------ router ----
----
----
----

The WAN side uses the public ISP IP address. The LAN side
uses the private IP addresses dished out by DHCP running
on the router.

If you "bridge" the cable modem, the router is disabled...
Similarly, if you had an older unit, it might just be
a modem. The output of bridged things, can be PPPOE,
and then a username/password is required to "log into"
the ISP. Windows 7 can sniff this situation, and it
will use its PPPOE termination stack. Seeing a public
address in "ipconfig", would confirm the usage of PPPOE
(like if someone else set it up and you were "just a victim").

DOCSIS
<Cable>------ modem ------ <PPPOE> --- Win7 terminates PPPOE
Machine has a *public*
address, outside the
192.168.x.x or 10.x.x.x
range.

I expect your cable modem, is a combo modem/router, running
in "normal mode", and the first diagram applies.

*******

Note that some network failures, are the result of subsystems
in the OS. For example, the networking stack uses .NET libraries.
(The similarity of names there is purely coincidental.)

Some executables need "runtime compilation" after a .NET update.
On WinXP, the firewall in particular, can foul up after a .NET
update and there is an "ngen" command to force the .NET assemblies
to be recompiled. This can take around ten minutes, to do all the
system executables which have .NET dependencies. This isn't likely
to be the reason on Win7 (it doesn't have this "ngen bug"), but I
mention the subsystems as potential culprits. (There can be a
pregnant pause until this baloney is finished in the background.)
In addition, malware that upsets certain networking stack settings,
could also be responsible for fouling up the connection, and then the
"netsh" commands the Troubleshooter uses, kinda sorta makes it
work again.

You could be connecting via IPV4 or IPV6. I'm IPV4-only here, so I
cannot comment on the early morning dynamics of IPV6 coming up
on a broadband device. I presume Microsoft still does the same
"basic networking test" for the "healthy network" icon to show.

Paul

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