uPNP - what is it?

[#1]

[quote=A Fox is Evil ]I tried the static address approach - but although I could ping the PC's static address, it failed to find the gateway (router) address
I reckon you have a DNS problem with your gateway.
On a Windows PC in the network Internet Protocol properties try setting -
"Obtain an IP address automatically"
and
"Use the following DNS server addresses:"
"Preferred DNS server:" = "8.8.4.4"
"Alternate DNS server:" = "208.67.220.220"
Save those settings and shutdown the PC.
Reboot the gateway and wait until the internet connection is established.
Start the PC, and report back whether it works AND the results of "ipconfig /all" as you did previously.

[#2]

@Purleigh (with the penguin) you are an absolute star!!!! 
Although your instructions relate to another incarnation of Windows (not XP),
I now have a setup that uses DHCP for ip and specified DNS addresses - but it works as I am writing this on said machine!
I didn't reboot my router though,
I didn't even reboot Windows
I used the ipconfig /renew command line option

Quote

Windows IP Configuration         Host Name . . . . . . . . . . . . : DALEK         Primary Dns Suffix  . . . . . . . :         Node Type . . . . . . . . . . . . : Hybrid         IP Routing Enabled. . . . . . . . : No         WINS Proxy Enabled. . . . . . . . : No Ethernet adapter Wireless Connection 2:         Connection-specific DNS Suffix  . :         Description . . . . . . . . . . . : Atheros AR5006EG Wireless Network Adapter         Physical Address. . . . . . . . . : 00-16-E3-65-9B-55         Dhcp Enabled. . . . . . . . . . . : Yes         Autoconfiguration Enabled . . . . : Yes         IP Address. . . . . . . . . . . . : 192.168.1.64         Subnet Mask . . . . . . . . . . . : 255.255.255.0         Default Gateway . . . . . . . . . : 192.168.1.1         DHCP Server . . . . . . . . . . . : 192.168.1.1         DNS Servers . . . . . . . . . . . : 8.8.4.4                                             208.67.220.220         Lease Obtained. . . . . . . . . . : 05 June 2010 17:41:14         Lease Expires . . . . . . . . . . : 06 June 2010 17:41:14

I'll switch the Windows firewall back on now.
Once again, thank you
Windows is weird.

[#3]

Quote from: A

Windows is weird.

Your router configuration is weird methinks. 

[#4]

Usually at this point I start moaning that the PlusNet DNS are messed up which in turn USED to stuff my Linksys gateway/router DNS responses, BUT I have just run repeated tests on the various DNS's and if anything the PlusNet DNS's are working perfectly and appear to be faster than I usually see !
The DNS entry 192.168.2.5 is one of my Ubuntu boxes running "dnsmasq", and since I started running this configuration, my network is much more resilient to DNS outages, and as you can see is much quicker as well ! 
Anyway I am glad your Windows machines are working now, even if we still don't quite know what went wrong !

[#5]

[quote=A Fox is Evil ]My windows PC's keep having intermittent wireless problems, whilst Linux "just works".
Just out of interest, have your Windows PC ever worked reliably, or is it only in say the last month that this problem started ?

[#6]

Well, all my wireless - Windows (or Linux) has always worked reliability.
(Famous last words  )
However...
Recently I was forced to buy a new router, because my Dlink 2640 suddenly decided to intermittently fail wirelessly.
I have recently replaced it with a Netgear DG834Gv5 - not ideal, but the v4 is only available second hand.
I didn't make any changes to any of my PC's and it worked OK initially - but somewhere during my configuration, I upset M$
I changed the SSID and set encryption to WPA(PSK-TKIP) - same security pass-phrase, so my PC's didn't require any config changes.
Only major change appears to be that the DHCP lease period changed from 4 days to one day (the new router doesn't appear to let me change this).

[#7]

The lease period can probably be changed by command line though appears to be inaccessible through the web interface.
DGTeam firmware has the option, at least it does on my DG834GT, not sure about the Gv5.
Many Windows systems get very confused if you keep an SSID unchanged but change security settings, it hangs on to the old values and fails with unhelpful errors.
The best thing to do is to fully delete the specific network in Windows, let it find it again and it determines the type correctly and asks you to re-enter the key.
(or you can go into the Advanced area and change it manually)

[#8]

The trouble is that I have seen several friends apparently having DNS problems in the last few weeks, and there a couple of threads on this forum reporting similar troubles.
I am wondering if it is just a coincidence that there has been a recent cluster of DNS problems, where the symptoms appear to be that Windows has DNS problems when pointing at the local gateway/router DNS, BUT the problem disappears when setting Windows to use external DNS servers directly !.
I wonder if it anything to do with the worldwide change last month to the DNS system - http://www.theregister.co.uk/2010/04/13/dnssec/
From what I have seen so far -
1)  the problem exists when using at least three different makes of gateway/router.
2)  it seems to affect Windows machines but Ubuntu seems more resilient.
3)  the problem occurs then the primary DNS is one of PlusNet's addresses, I have not yet seen failures using OpenDNS or Google DNS.
4)  if Windows XP primary DNS points at local gateway (using PlusNet DNS) and secondary DNS points to OpenDNS or Google, once problem occurs then Windows does NOT fallback to using the secondary DNS. - WHY
5)  using a local Linux DNS server (BIND or DNSMASQ) and the problem for all machines (especially Windows XP) is permanently resolved, no matter what external DNS is being used.

[#9]

I'm using dnsmasq on ubuntu but I get

Quote

$dig +short rs.dns-oarc.net txt rst.x476.rs.dns-oarc.net. rst.x485.x476.rs.dns-oarc.net. rst.x490.x485.x476.rs.dns-oarc.net. "212.159.6.136 DNS reply size limit is at least 490" "212.159.6.136 lacks EDNS, defaults to 512" "Tested at 2010-06-06 16:51:59 UTC"

So it's a bit dodgy?
My router is setup to take settings from Plusnet though.

[#10]

Slightly off topic but the DNSSEC stuff certainly shouldn't present any problems.
It's only an issue if DNSSEC is configured, but EDNS is not. This leads to responses that are too large for the resolver to deal with.
We're using PowerDNS which supports DNSSEC but it's a relatively new feature of the software so it's not switched on at the moment.
That means we have neither DNSSEC nor EDNS configured so there shouldn't be any issues.
The changes do have overhead implications, but again this isn't something we've any reason to believe is causing problems.

[#11]

Does this mean that Plusnet have no access to the root DNS servers then?

[#12]

Not as I understand it it doesn't no.