Windows loses DNS capability periodically - reboot fixes

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Guest

Can anyone point me to a solution to this problem which has only been
occuring for about a couple of weeks:

After XP has been running for a time (say 24 hours) it loses the capability
to resolve internet addresses.. IE/Firefox just say "looking up xxx.." OE
can't reach the mail server. There's nothing physically amiss - I can still
access the internet via IP addresses.

I have only the one pc connected to the router; restarting the router
doesn't have any effect - and my browser can't even resolve the router
address "http://speedtouch.lan" at such times - but restarting Windows always
fixes things at once... until the next time..

I don't know where to start looking in the case of such an intermittent
problem. Any advice would be gratefully received.

Walter
 
from an command prompt run

ipconfig /flushdns

does this fix the issue?

please post the text output from ipconfig /all run from the command
prompt.

Can anyone point me to a solution to this problem which has only been
occuring for about a couple of weeks:

After XP has been running for a time (say 24 hours) it loses the capability
to resolve internet addresses.. IE/Firefox just say "looking up xxx.." OE
can't reach the mail server. There's nothing physically amiss - I can still
access the internet via IP addresses.

I have only the one pc connected to the router; restarting the router
doesn't have any effect - and my browser can't even resolve the router
address "http://speedtouch.lan" at such times - but restarting Windows always
fixes things at once... until the next time..

I don't know where to start looking in the case of such an intermittent
problem. Any advice would be gratefully received.

Walter
Click to expand...
--

Barb Bowman
MS Windows-MVP
http://www.microsoft.com/windowsxp/expertzone/meetexperts/bowman.mspx
http://blogs.digitalmediaphile.com/barb/
 
Current response from ipconfig /all (while all working well) is:

Windows IP Configuration

Host Name . . . . . . . . . . . . : walter-df1186df
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Unknown
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No
DNS Suffix Search List. . . . . . : lan

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . : lan
Description . . . . . . . . . . . : Realtek RTL8139 Family PCI Fast
Ethe
rnet NIC
Physical Address. . . . . . . . . : 00-15-F2-57-66-7A
Dhcp Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
IP Address. . . . . . . . . . . . : 192.168.1.64
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.1.254
DHCP Server . . . . . . . . . . . : 192.168.1.254
DNS Servers . . . . . . . . . . . : 192.168.1.254
Lease Obtained. . . . . . . . . . : 19 October 2007 09:49:17
Lease Expires . . . . . . . . . . : 20 October 2007 09:49:17

Will do again and also /flushdns when I next lose connectivity and post
again.

Thanks

Walter
 
Just an update.

I lost connectivity again once yesterday and when I ran ipconfig /all before
rebooting (forgot to copy/paste!) I noted that the "Lease Expires" value was
in the past.. Could this be the immediate cause of the symptom?

This would then make my question "What causes this value to update in XP,
and what might cause it not to update at appropriate times?" Observation
suggests that a new 24-hour lease is "obtained" at approximately 12-hourly
intervals - currently at 09.10 local time it's showing "Lease Expires 22.59"
today.

Or am I on the wrong track?

Walter
 
if your computer was turned off/hibernating etc., the lease may
expire when it is in this state. a better driver for you NIC might
fix this (and/or a firmware upgrade for your router), and you can
also set the lease time on most routers to be a longer period in the
admin pages (which will certainly make this happen less often). If
you don't have a lot of computers on your network, you could set for
the longest time possible. Still if there is an issue with the
computer receiving DHCP OFFER messages from the router or if the
router isn't sending them properly, this could continue.

what router model and hardware revision and what firmware version?

Just an update.

I lost connectivity again once yesterday and when I ran ipconfig /all before
rebooting (forgot to copy/paste!) I noted that the "Lease Expires" value was
in the past.. Could this be the immediate cause of the symptom?

This would then make my question "What causes this value to update in XP,
and what might cause it not to update at appropriate times?" Observation
suggests that a new 24-hour lease is "obtained" at approximately 12-hourly
intervals - currently at 09.10 local time it's showing "Lease Expires 22.59"
today.

Or am I on the wrong track?

Walter
Click to expand...
--

Barb Bowman
MS Windows-MVP
http://www.microsoft.com/windowsxp/expertzone/meetexperts/bowman.mspx
http://blogs.digitalmediaphile.com/barb/
 
Many thanks for taking an interest in this. I feel that now I've got some
clues I should be researching this off my own bat.. But, since you're
there...(!)

I only have a single device - a desktop PC - attached to the router - a
Thompson Speedtouch - Release 6.1.4.6 . I do see in Router Configuration an
option against IP Address to "Always use the same IP Address". So presumably
I should try this?

[The manual actually seems a bit out of synch with the firmware - it
indicates that you can set a similar flag against the "DHCP" pool to "Always
give same address to DHCP clients", which will set the "lease time" to
infinite, or set specific values for the "lease time" - but these I can't in
fact find any way to do.]

But am I right to suppose that something has, in a sense, broken? I don't
understand why I'd never even been aware of "leases" before, and how this has
become a problem, granted a minor one, only for the last two weeks.. You
mentioned "DHCP OFFER" messages from the router - are these in general
triggered every few seconds/minutes, or only as the lease comes close to
expiry? And is there any logging anywhere that would show them? Or is the
"lease" usually infinite, in fact?

Regards

Walter
 
you should double check the vendor website to make sure that the
firmware you list against the latest. DHCP reservation - always
given the same IP - is the one you should use (but it still won't be
infinite so set the lease time to the longest one possible).

the other thing is that the router may have stopped proxying DNS
requests. find out the DNS servers used by your ISP (they ay appear
on the router config pages) and enter them in the computer TCP/IP
config as static DNS servers.

Many thanks for taking an interest in this. I feel that now I've got some
clues I should be researching this off my own bat.. But, since you're
there...(!)

I only have a single device - a desktop PC - attached to the router - a
Thompson Speedtouch - Release 6.1.4.6 . I do see in Router Configuration an
option against IP Address to "Always use the same IP Address". So presumably
I should try this?

[The manual actually seems a bit out of synch with the firmware - it
indicates that you can set a similar flag against the "DHCP" pool to "Always
give same address to DHCP clients", which will set the "lease time" to
infinite, or set specific values for the "lease time" - but these I can't in
fact find any way to do.]

But am I right to suppose that something has, in a sense, broken? I don't
understand why I'd never even been aware of "leases" before, and how this has
become a problem, granted a minor one, only for the last two weeks.. You
mentioned "DHCP OFFER" messages from the router - are these in general
triggered every few seconds/minutes, or only as the lease comes close to
expiry? And is there any logging anywhere that would show them? Or is the
"lease" usually infinite, in fact?

Regards

Walter

Barb Bowman said:
if your computer was turned off/hibernating etc., the lease may
expire when it is in this state. a better driver for you NIC might
fix this (and/or a firmware upgrade for your router), and you can
also set the lease time on most routers to be a longer period in the
admin pages (which will certainly make this happen less often). If
you don't have a lot of computers on your network, you could set for
the longest time possible. Still if there is an issue with the
computer receiving DHCP OFFER messages from the router or if the
router isn't sending them properly, this could continue.

what router model and hardware revision and what firmware version?
Click to expand...
Click to expand...
--

Barb Bowman
MS Windows-MVP
http://www.microsoft.com/windowsxp/expertzone/meetexperts/bowman.mspx
http://blogs.digitalmediaphile.com/barb/
 
Think the lease may have been a false lead.. Latest loss of connectivity was
while within the first twelve hours of a twenty-four hour lease.. so there
wouldn't even have been any attempt to renew it at that point.

I'll try setting the DNS values in my TCP/IP config - currently set to
automatic - and see what effect that has.

Walter
 
thanks for the update, please keep us posted.

Think the lease may have been a false lead.. Latest loss of connectivity was
while within the first twelve hours of a twenty-four hour lease.. so there
wouldn't even have been any attempt to renew it at that point.

I'll try setting the DNS values in my TCP/IP config - currently set to
automatic - and see what effect that has.

Walter
Click to expand...
--

Barb Bowman
MS Windows-MVP
http://www.microsoft.com/windowsxp/expertzone/meetexperts/bowman.mspx
http://blogs.digitalmediaphile.com/barb/
 
Three days of trouble-free operation suggests that this may have been the
solution.

While I'm happy with this, does it imply that the router has been at fault
in recent weeks or that I should have set those values for TCP/IP in Windows
from the start? Remember the problem only started up out of the blue a few
weeks ago.. in fact, my impression is that I'm getting slightly faster
responses now anyway, so it's a win all round.
 
Some routers have a setting that toggles the "proxy" of DNS on and
off. It is hard to say what combination of things causes proxying
not to work. But since some routers DO have this toggle, it implies
that there is a need in some cases to have the client computers not
use the proxy DNS of the router.

It could have been a driver update or windows update that caused
this if it was previously working and then stopped. Or even an
update to your anti virus/firewall software.

Three days of trouble-free operation suggests that this may have been the
solution.

While I'm happy with this, does it imply that the router has been at fault
in recent weeks or that I should have set those values for TCP/IP in Windows
from the start? Remember the problem only started up out of the blue a few
weeks ago.. in fact, my impression is that I'm getting slightly faster
responses now anyway, so it's a win all round.
Click to expand...
--

Barb Bowman
MS Windows-MVP
http://www.microsoft.com/windowsxp/expertzone/meetexperts/bowman.mspx
http://blogs.digitalmediaphile.com/barb/
 
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