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Win 8.1: DHCP no longer getting an IP address



 
 
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  #1  
Old January 19th 18, 02:42 PM posted to alt.windows7.general
NY
external usenet poster
 
Posts: 586
Default Win 8.1: DHCP no longer getting an IP address

A Windows 8.1 PC which was set up to connect to a wifi network stopped
connecting to the internet a few days ago. On investigation, I found that it
was not getting an IP address: instead IPCONFIG reported a 169.x.x.x
address. This also happened with another wifi network (an Android phone with
mobile-to-wifi tethering enabled) and with the original router connected by
Ethernet. I tried with the router rebooted, and I forgot and re-added the
wifi connection.

I checked that the DHCP service was running. I couldn't find any DHCP events
in any of the Event Logs, with the exception of service started/stopped
events when restarting the PC.

I also disabled IPV6 to force the PC to use IPV4 DHCP, but no change.

I opened an elevated CMD ("run as administrator") and ran "netsh winsock
reset" which appeared to complete without any error message, and I then
rebooted, but this didn't solve the problem either.

"ipconfig /release" appeared to succeed but "ipconfig /renew" hung and never
completed and never gave an error message - this was also from elevated CMD
prompt.

Setting either wifi or Ethernet connection's IPV4 config to static
IP/gateway/DNS worked fine.


The user had already tried restoring the PC to an earlier restore point from
before the problem occurred, but that failed after a long time with a bland
"could not restore to earlier restore point" error (don't you just love it
when that happens - probably 50% of the time I try to restore a PC to fix
some problem, it fails to do so with that sort of message).


I left the PC with a static IP, choosing one which was within the subnet but
outside the router's DHCP scope, and warnings that it may fail if it was
ever connected to another network which didn't have the same subject and
gateway (ie not 192.168.1.x for IP and 192.168.1.254 for gateway and DNS).


Is there anything else I should have tried before going for the pragmatic
static-IP solution?

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  #2  
Old January 19th 18, 04:38 PM posted to alt.windows7.general
NY
external usenet poster
 
Posts: 586
Default Win 8.1: DHCP no longer getting an IP address

"Wolf K" wrote in message
...
Get a new router? If all those attempts at fixing the software failed, it
looks like a hardware problem to me.

IMO, a router more than a couple or years old doesn't owe you anything.
Latest flyer from the local pusher showed routers specced twice as good as
my ancient one for less than half its original price. So if it ever
hiccups, it's in the dumpster. :-)


I'd have suspected the router except for one fact: the problem exists with a
different DHCP server - the tethering feature on an Android phone. I tried
that early on to try to eliminate the router as the faulty component.

I forgot to mention (fairly important - sorry!) that other devices (laptops,
mobile phones) can connect to the existing router either by wifi or
Ethernet.

  #3  
Old January 19th 18, 07:27 PM posted to alt.windows7.general
NY
external usenet poster
 
Posts: 586
Default Win 8.1: DHCP no longer getting an IP address

"KenW" kenw@ noplace.com wrote in message
...
If your connected via cat cable, substitute it.


I know that having more than one fault is not impossible, but I *think* that
my testing showed:

1. fault affects one laptop making wifi connection to router and to DHCP
server and mobile-to-wifi bridge (tethering) on Android phone: two different
router-like devices with two different DHCP servers

2. fault affects both wifi and Ethernet on this laptop

3. fault does not affect other computers (laptop by wifi, desktop by
Ethernet using the same cable tested in 2, mobile phone by wifi)

4, affected laptop appears to work fine with a static IP address (can
browse, get POP email, ping, nslookup)

Seems to point to the DHCP client on this particular PC, in code which is
shared between wifi and Ethernet. "ipconfig /renew" fails to complete,
giving no error message - something's amiss there.

Eliminated simple fixes like (re)starting DHCP service, clearing and
resetting winsock config (netsh winsock reset).


Task was to get PC working. After doing *some* troubleshooting, it was not
worth starting on bigger fixes like reinstalling Windows or working out why
System Restore was failing (as so often happens - grr). Quick fix with
limitations (will fail on non-192.168.1.x network) is better than perfect
fix that takes considerably longer.

It would have been interesting to see what DHCP traffic is passing between
laptop and router: is laptop failing to request DHCP address or is it
failing to understand the router's (DHCP server's) response? Didn't have a
computer with LAN trace software to look at this.


From people's responses so far, it sounds as if I haven't forgotten to check
anything *too* obvious.

  #4  
Old January 19th 18, 07:31 PM posted to alt.windows7.general
VanguardLH[_2_]
external usenet poster
 
Posts: 10,881
Default Win 8.1: DHCP no longer getting an IP address

NY wrote:

A Windows 8.1 PC which was set up to connect to a wifi network stopped
connecting to the internet a few days ago. On investigation, I found that it
was not getting an IP address: instead IPCONFIG reported a 169.x.x.x
address. This also happened with another wifi network (an Android phone with
mobile-to-wifi tethering enabled) and with the original router connected by
Ethernet. I tried with the router rebooted, and I forgot and re-added the
wifi connection.

I checked that the DHCP service was running. I couldn't find any DHCP events
in any of the Event Logs, with the exception of service started/stopped
events when restarting the PC.

I also disabled IPV6 to force the PC to use IPV4 DHCP, but no change.

I opened an elevated CMD ("run as administrator") and ran "netsh winsock
reset" which appeared to complete without any error message, and I then
rebooted, but this didn't solve the problem either.

"ipconfig /release" appeared to succeed but "ipconfig /renew" hung and never
completed and never gave an error message - this was also from elevated CMD
prompt.

Setting either wifi or Ethernet connection's IPV4 config to static
IP/gateway/DNS worked fine.

The user had already tried restoring the PC to an earlier restore point from
before the problem occurred, but that failed after a long time with a bland
"could not restore to earlier restore point" error (don't you just love it
when that happens - probably 50% of the time I try to restore a PC to fix
some problem, it fails to do so with that sort of message).

I left the PC with a static IP, choosing one which was within the subnet but
outside the router's DHCP scope, and warnings that it may fail if it was
ever connected to another network which didn't have the same subject and
gateway (ie not 192.168.1.x for IP and 192.168.1.254 for gateway and DNS).

Is there anything else I should have tried before going for the pragmatic
static-IP solution?


For my wifi cable/voice modem, resetting it wipes it back to factory
defaults. That means the wifi passwords I specified for the 2.4 and 5
GHz bands were cleared. If I use a paper clip to momentarily press the
modem's reset button, the unit only restarts. If I long-press its reset
button (continuously for longer than 10 seconds), it resets back to
factory defaults. I've had to reset a couple of times thereafter all
the wifi devices could not connect. I had to go into the router's
config to restore the wifi passwords. I don't recall have to re-pair.

If did any other tweaking of the router beyond the wifi passwords, like
using MAC or IP filtering as to which devices are allowed to connect to
the router, or port forwarding, or changing the security level of its
firewall, you might want to reset the router, just reenter the same wifi
passwords in the router, and retest the IoTs that couldn't connect
before but would now use a default config in the router. Rebooting or
restarting the router is not the same as a reset of the router.

  #5  
Old January 19th 18, 07:44 PM posted to alt.windows7.general
Char Jackson
external usenet poster
 
Posts: 10,449
Default Win 8.1: DHCP no longer getting an IP address

On Fri, 19 Jan 2018 18:27:35 -0000, "NY" wrote:

It would have been interesting to see what DHCP traffic is passing between
laptop and router: is laptop failing to request DHCP address or is it
failing to understand the router's (DHCP server's) response? Didn't have a
computer with LAN trace software to look at this.


I agree, it might have been interesting to see what's going on down at
that layer.

You might install WinDump and Wireshark on a working PC to get a feel
for what a successful DHCP transaction looks like, if you're not already
familiar. That would prepare you to do a similar test on the problem
child to see what's different. From reading your description of events,
I'm guessing it's not sending a DHCP request, or perhaps it's malformed
in some way so that the DHCP server rejects it as invalid. Either way,
after not getting a response, the laptop then does what it's supposed to
do: auto assign an APIPA address (169.254.x.x/16).

Is this issue something that used to work until one day it didn't, or
did it never work?

--

Char Jackson
  #6  
Old January 19th 18, 07:46 PM posted to alt.windows7.general
Char Jackson
external usenet poster
 
Posts: 10,449
Default Win 8.1: DHCP no longer getting an IP address

On Fri, 19 Jan 2018 12:31:07 -0600, VanguardLH wrote:

If did any other tweaking of the router beyond the wifi passwords, like
using MAC or IP filtering as to which devices are allowed to connect to
the router, or port forwarding, or changing the security level of its
firewall, you might want to reset the router, just reenter the same wifi
passwords in the router, and retest the IoTs that couldn't connect
before but would now use a default config in the router. Rebooting or
restarting the router is not the same as a reset of the router.


MAC filtering is a good tip. That would cause what they're seeing.

--

Char Jackson
  #7  
Old January 19th 18, 09:14 PM posted to alt.windows7.general
J. P. Gilliver (John)[_4_]
external usenet poster
 
Posts: 2,679
Default Win 8.1: DHCP no longer getting an IP address

In message , Wolf K
writes:
[]
Get a new router? If all those attempts at fixing the software failed,
it looks like a hardware problem to me.

IMO, a router more than a couple or years old doesn't owe you anything.
Latest flyer from the local pusher showed routers specced twice as good
as my ancient one for less than half its original price. So if it ever
hiccups, it's in the dumpster. :-)

I'd say just because "better and cheaper" is available, is not a reason
to ditch something that might be working - especially if the respect in
which it is "better" is not relevant (e. g. router offers an [A]DSL
protocol not supported by the exchange, or wifi to 802.11N when all the
equipment is in the same room).

[FWIW, I'm using a router that was the cheapest I could find when I
bought it (which was just before the wired-only router my ISP supplied
died - so you can guess how long ago that was!), and it's been powered
for several years now, excluding power cuts, and touch wood never given
me any trouble. (The odd reboot has been necessary, maybe once to thrice
a year; those could equally be due to the exchange equipment.) It's a
"Dynamode R-ADSL-C4-W-G1" according to what's printed on top.]
--
J. P. Gilliver. UMRA: 1960/1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

Where [other presenters] tackle the world with a box of watercolours, he
takes a spanner. - David Butcher (on Guy Martin), RT 2015/1/31-2/6
  #8  
Old January 19th 18, 09:57 PM posted to alt.windows7.general
NY
external usenet poster
 
Posts: 586
Default Win 8.1: DHCP no longer getting an IP address

"Char Jackson" wrote in message
...
On Fri, 19 Jan 2018 12:31:07 -0600, VanguardLH wrote:

If did any other tweaking of the router beyond the wifi passwords, like
using MAC or IP filtering as to which devices are allowed to connect to
the router, or port forwarding, or changing the security level of its
firewall, you might want to reset the router, just reenter the same wifi
passwords in the router, and retest the IoTs that couldn't connect
before but would now use a default config in the router. Rebooting or
restarting the router is not the same as a reset of the router.


MAC filtering is a good tip. That would cause what they're seeing.


Fair point. But the user said everything was working perfectly until a few
days ago when it suddenly stopped, possibly after a Windows update. He
wouldn't know how to access the router to set up MAC filtering.

  #9  
Old January 19th 18, 09:58 PM posted to alt.windows7.general
NY
external usenet poster
 
Posts: 586
Default Win 8.1: DHCP no longer getting an IP address

"Char Jackson" wrote in message
...
On Fri, 19 Jan 2018 18:27:35 -0000, "NY" wrote:

It would have been interesting to see what DHCP traffic is passing between
laptop and router: is laptop failing to request DHCP address or is it
failing to understand the router's (DHCP server's) response? Didn't have a
computer with LAN trace software to look at this.


I agree, it might have been interesting to see what's going on down at
that layer.

[...]
Is this issue something that used to work until one day it didn't, or
did it never work?


It used to work until one day (maybe after a Windows update) it stopped.

  #10  
Old January 19th 18, 10:03 PM posted to alt.windows7.general
VanguardLH[_2_]
external usenet poster
 
Posts: 10,881
Default Win 8.1: DHCP no longer getting an IP address

NY wrote:

"Char Jackson" wrote in message
...
On Fri, 19 Jan 2018 12:31:07 -0600, VanguardLH wrote:

If did any other tweaking of the router beyond the wifi passwords, like
using MAC or IP filtering as to which devices are allowed to connect to
the router, or port forwarding, or changing the security level of its
firewall, you might want to reset the router, just reenter the same wifi
passwords in the router, and retest the IoTs that couldn't connect
before but would now use a default config in the router. Rebooting or
restarting the router is not the same as a reset of the router.


MAC filtering is a good tip. That would cause what they're seeing.


Fair point. But the user said everything was working perfectly until a few
days ago when it suddenly stopped, possibly after a Windows update. He
wouldn't know how to access the router to set up MAC filtering.


The point was to reset the router/modem back to factory defaults and
only reenter the wifi passwords back into the router (so the IoTs don't
have to each have their wifi password changed).
  #11  
Old January 19th 18, 11:18 PM posted to alt.windows7.general
Char Jackson
external usenet poster
 
Posts: 10,449
Default Win 8.1: DHCP no longer getting an IP address

On Fri, 19 Jan 2018 15:03:46 -0600, VanguardLH wrote:

NY wrote:

"Char Jackson" wrote in message
...
On Fri, 19 Jan 2018 12:31:07 -0600, VanguardLH wrote:

If did any other tweaking of the router beyond the wifi passwords, like
using MAC or IP filtering as to which devices are allowed to connect to
the router, or port forwarding, or changing the security level of its
firewall, you might want to reset the router, just reenter the same wifi
passwords in the router, and retest the IoTs that couldn't connect
before but would now use a default config in the router. Rebooting or
restarting the router is not the same as a reset of the router.

MAC filtering is a good tip. That would cause what they're seeing.


Fair point. But the user said everything was working perfectly until a few
days ago when it suddenly stopped, possibly after a Windows update. He
wouldn't know how to access the router to set up MAC filtering.


The point was to reset the router/modem back to factory defaults and
only reenter the wifi passwords back into the router (so the IoTs don't
have to each have their wifi password changed).


I believe he said he tried tethering to another access point, (a cell
phone?), so if the issue isn't limited to the router I'd be inclined to
rule out said router. If multiple AP's cause the issue, it's more likely
to be in the client.

--

Char Jackson
  #12  
Old January 19th 18, 11:44 PM posted to alt.windows7.general
Mike S[_4_]
external usenet poster
 
Posts: 496
Default Win 8.1: DHCP no longer getting an IP address

On 1/19/2018 10:27 AM, NY wrote:
2. fault affects both wifi and Ethernet on this laptop


I had a strange problem where a laptop stopped connecting to a router
for no apparent reason, all of the settings looked fine. I removed the
hardware from the Device manager, rebooted and let Windows reinstall it,
and is started working normally again. You might consider removing both
the ethernet and wifi adapters then rebooting.
  #13  
Old January 20th 18, 09:12 AM posted to alt.windows7.general
VanguardLH[_2_]
external usenet poster
 
Posts: 10,881
Default Win 8.1: DHCP no longer getting an IP address

NY wrote:

"Char Jackson" wrote in message
...
On Fri, 19 Jan 2018 12:31:07 -0600, VanguardLH wrote:

If did any other tweaking of the router beyond the wifi passwords, like
using MAC or IP filtering as to which devices are allowed to connect to
the router, or port forwarding, or changing the security level of its
firewall, you might want to reset the router, just reenter the same wifi
passwords in the router, and retest the IoTs that couldn't connect
before but would now use a default config in the router. Rebooting or
restarting the router is not the same as a reset of the router.


MAC filtering is a good tip. That would cause what they're seeing.


Fair point. But the user said everything was working perfectly until a few
days ago when it suddenly stopped, possibly after a Windows update. He
wouldn't know how to access the router to set up MAC filtering.


If he doesn't know how to access the router's internal web server to get
at the config screens then how did the wifi passwords ever get set? If
he has never configured the router then it is still using the factory
default for login (probably username = "admin" & password = "password")
which means anyone can hack through his router to get his intranet
hosts.
  #14  
Old January 20th 18, 12:06 PM posted to alt.windows7.general
J. P. Gilliver (John)[_4_]
external usenet poster
 
Posts: 2,679
Default Win 8.1: DHCP no longer getting an IP address

In message , VanguardLH
writes:
[]
If he doesn't know how to access the router's internal web server to get
at the config screens then how did the wifi passwords ever get set? If
he has never configured the router then it is still using the factory
default for login (probably username = "admin" & password = "password")
which means anyone can hack through his router to get his intranet
hosts.


What you say is right, other than calling them "the wifi passwords". The
wifi passwords will (in UK anyway, for ISP-provided routers at least)
usually be a string of characters, and on a label on the bottom of the
router. The ones you are referring to are the router control access
passwords (I don't know if that's the correct phrase, if there is a
"correct" phrase) - you'd still need them even if accessing the router
by other than wifi. Actually, on a recent ISP-supplied router I saw, the
label gave those too - and although the username _was_ admin, the
password was another string of characters, so maybe that door is
(slowly) closing, too.
--
J. P. Gilliver. UMRA: 1960/1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

Gravity is a myth; the Earth sucks.
  #15  
Old January 20th 18, 07:42 PM posted to alt.windows7.general
VanguardLH[_2_]
external usenet poster
 
Posts: 10,881
Default Win 8.1: DHCP no longer getting an IP address

J. P. Gilliver (John) wrote:

VanguardLH WROTE:

If he doesn't know how to access the router's internal web server to
get at the config screens then how did the wifi passwords ever get
set? If he has never configured the router then it is still using
the factory default for login (probably username = "admin" &
password = "password") which means anyone can hack through his
router to get his intranet hosts.


What you say is right, other than calling them "the wifi passwords".
The wifi passwords will (in UK anyway, for ISP-provided routers at
least) usually be a string of characters, and on a label on the
bottom of the router. The ones you are referring to are the router
control access passwords (I don't know if that's the correct phrase,
if there is a "correct" phrase) - you'd still need them even if
accessing the router by other than wifi. Actually, on a recent
ISP-supplied router I saw, the label gave those too - and although
the username _was_ admin, the password was another string of
characters, so maybe that door is (slowly) closing, too.


I was referring to TWO logins: one for the wifi passphrase(s) and the
other to log into the router's internal web server to configure it.

I remember finding a list of router models showing what are the default
login credentials to the routers. They're publicly listed hence well
known. That's why the first tweak a user should do to a router is to
change its login password (the username "admin" is often fixed so all
you get to change is the password string). The password should be
changed to a STRONG password. It's the first portal (attack vector)
that should get defended. If the low-level user hasn't a clue about
doing any configuration of their router, as claimed, then it's likely
the default login credentials are still defined in that router leaving
it vulnerable to /easy/ attack.
 




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