DNS problems when using fixed IP

[#1]

I need to assign my PC a static IP for port forwarding. I’m using Windows 7, a Thompson TG585 V8 router supplied by Plusnet, I’m on the Plusnet Pro broadband package, and my broadband firewall is set to ‘off’.
I can set up the static IP but I keep getting DNS problems. Sometimes when windows validates the ipv4 network adaptor configuration on exit it will say ‘The DNS server isn't responding’. Other times I can access the web but it takes longer than usual to resolve certain addresses and load images etc. Usually after a few minutes of this I will lose all internet connectivity. If I revert my network adaptor back to dynamic IP and ‘obtain DNS from server’ everything works perfectly again.
I'm using the following settings for my fixed IP, subnet mask and default gateway were obtained from my ipconfig when it was set to dynamic IP as per the advice on portforward.com
IP Address: 192.168.1.44
Subnet Mask: 255.255.255.0
Default Gateway: 192.168.1.254

I’ve tried different DNS with varying results, as follows.
DNS that shows in my ipconfig when I have dynamic ip setup (Primary DNS: 212.159.6.9, Secondary DNS: 212.159.6.10) doesn’t work at all when I use a fixed IP, I get the ‘The DNS server isn't responding’ message when validating on exiting network adaptor settings.
Open DNS (Primary DNS: 208.67.222.222, Secondary DNS: 208.67.220.220) works intermittently but slows to a halt after a few minutes.
DNS recommended by Plusnet works intermittently but slows to a halt after a few minutes.

I’m fairly tech savvy (I work in web) and I’ve done this many times before but this is the first time I’ve tried it since I switched to Plusnet. I’m using the guide at portforward.com to the letter so I just do not know what the problem is. Any help would be much appreciated.

[#2]

Rather than setting a fixed IP address in the PC, can you continue to use dynamic allocation (as far as the PC is concerned), then configure a fixed IP for that particular Device - probably against the MAC address - within the router?
Otherwise I always wonder whether routers have problems when we humans allocate a fixed IP address from within the range that they are allowed to freely allocate dynamically.
Perhaps you can try altering the configuration of the router so that the dynamic range is 100-250, so your manual allocation is outside the range.
Alternatively, you could try setting the DNS address (on the PC) to 192.168.1.254, and let the router worry about where to send requests onto.

[#3]

I have used a fixed DNS (openDNS) allocated to the network adaptor on one computer without any problems and I'm sure I am not alone in successfully using a non-Plusnet DNS server.  Now admittedly this is not in conjunction with a fixed IP address but surely that cannot make a difference.  So I don't think your problem is anything to do with Plusnet.  Have you an alternative router you could try?

[#4]

My network currently has 20+ devices all on static IPs using non-Plusnet DNSes (including OpenDNS), and it all works perfectly. 
If anything I used to have the opposite problem to the OP, where relying on my routers DHCP/DNS, the router's DNS cache seemed to go to sleep after a few days of usage and would only recover after a reboot. 
Changing to static IPs and manually set DNS fixed this problem, so I assume my router's firmware was not up to the job.   
As a result of these problems I now run a local DNS caching server that gives a better than 25 times DNS performance improvement compared to the Plusnet DNSes. 

[#5]

Quote from: purleigh

If anything I used to have the opposite problem to the OP, where relying on my routers DHCP/DNS, the router's DNS cache seemed to go to sleep after a few days of usage and would only recover after a reboot.    Changing to static IPs and manually set DNS fixed this problem, so I assume my router's firmware was not up to the job.

That was exactly my experience. I had to reboot my router about once a month as it got progressively slower.
My router is 192.168.0.1. I have a separate Wireless Access Point on 192.168.0.2. I've set the DHCP on the router to give out addresses in the range 192.168.0.9 to 192.168.0.99. My PCs I give static addresses starting from 192.168.0.100. The crucial thing is to make sure the static IP addresses are outside of the DHCP range.
On the PCs I've set the DNS to two PN ones then the two Google DNS servers.
One other thing I found useful to improve accessing shared resources on the PCs was to put entries in the hosts files (C:\Windows\System32\drivers\etc\hosts) for all the PCs.

[#6]

Quote from: WWWombat

Rather than setting a fixed IP address in the PC, can you continue to use dynamic allocation (as far as the PC is concerned), then configure a fixed IP for that particular Device - probably against the MAC address - within the router? Otherwise I always wonder whether routers have problems when we humans allocate a fixed IP address from within the range that they are allowed to freely allocate dynamically. Perhaps you can try altering the configuration of the router so that the dynamic range is 100-250, so your manual allocation is outside the range. Alternatively, you could try setting the DNS address (on the PC) to 192.168.1.254, and let the router worry about where to send requests onto.

Thanks.
I can configure port forwarding for a specific MAC address or device name within the router and I presume this *should* negate the need for a fixed IP in the PC. When I tried this, however, the applications that require port forwarding are not work correctly and they're telling me that my port is not open.
The router dynamic IP range is 64-253 and I'm using 44 so that shouldn't be a problem.
I think the router must have firmware specific to Plusnet because all my details are preconfigured and I'm unable to edit them, I can't even edit the router DNS settings!
One thing that I’m not sure about is an option called ‘Auto-IP Enabled’ in the router settings. It’s currently unchecked but there is no mention in the router help files about what this does and no amount of googling has turned up an answer. See here – http://s134415674.websitehome.co.uk/router.jpg
Will try your suggestion (setting PC DNS to 192.168.1.254).

[#7]

Right, in total I’ve spent literally about six hours trying to fix this and I’m now seriously beginning to question my sanity! 
I tried WWWombat’s suggestion of setting the DNS of the static IP on the PC to 192.164.1.254 to let the router worry about where to send requests. That got the static IP working fine and without the DNS issues I was having before. So far so good. But despite setting up port forwarding on the router to the new fixed IP my PF Port Checker app was still saying that the ports were closed on my PC. I tried rebooting PC and router but to no avail.
Then I found a setting hidden away in the router admin control panel on each connected device that ensures that each MAC address is always assigned the same IP address. So as per WWWombat’s original suggestion I ditched the fixed IP on my PC and reverted to dynamic IP but ensured that the router assigned my PC with the same IP every time. I then set up the port forwarding again to the new fixed IP. That all worked fine. So far so good. I tried PF Port Checker and port 13377 was open on TCP and UDP, all good. However, 12327 was open on TCP but closed on UDP. I went back and double checked the port forward setting but UDP on port 12327 is definitely forwarded to my PC. Cue a slight sigh and scratch of head.
So I checked again half an hour and a couple of reboots later. IP address unchanged as expected but now port 12327 is closed on TCP and UDP, and port 13377 is closed on TCP but still open on UDP. What the F...!! Nothing has changed and I’m now getting different results. The application that uses 12327 now won’t even connect.
I’m at a complete loss as to what is going on here unless this is a traffic shaping issue but I’m on the Pro package which supposed to have little or no traffic shaping applied.
I’m astonished that something that took two minutes to set up on every other ISP/Router I’ve had could be such a pain in the butt. It’s certainly not made any easier by the Plusnet firmware on the TG585 V8 router which is locked down and unintuitive.
Any ideas?

[#8]

Just a general response, this one...
I have a separate Linux box running both a DNS caching server, and a DHCP server. The DHCP has a subrange (100-199) for dynamic allocation, and the rest I choose manually. I then configure it with MAC addresses for most of the equipment around here.
The DHCP server also, when allocating IP Addresses, sends out the IP Address of that box as the DNS server. The DNS caching server is then configured to defer to Plusnet's 2 main DNS servers.
I've come across some  routers that seem to not like handling traffic from an IP address that it doesn't think it allocated during DHCP. So I make sure my fixed & dynamic ranges are mutually exclusive.
I don't normally have problems in the network, unless I have to take the Linux box out for a while. I then usually turn on the router's DHCP for a while, but it doesn't always work cleanly 😉

[#9]

Quote from: garyw

I can configure port forwarding for a specific MAC address or device name within the router and I presume this *should* negate the need for a fixed IP in the PC. When I tried this, however, the applications that require port forwarding are not work correctly and they're telling me that my port is not open.

That might work, but I've not come across that feature before. My router very much only allows me to specify a fixed IP Address for an incoming port.
When I have my Netgear router allocating IP Addresses, I set:
- The router has address 192.168.0.1
- Under LAN IP Config, I turn on the DHCP server
- I set address range to 192.168.0.25 - 192.168.0.254
- I then add entries into the "Address Reservation Table", so that a certain MAC address always gets 192.168.0.25, etc.
- I then add a rule into the firewall, that a certain port incoming gets allocated to 192.168.0.25.
The PC itself is set for dynamic DHCP, and dynamic DNS. When it works, the PC gets 192.168.0.25, with a gateway of 192.168.0.1, and a DNS address of 192.168.0.1
Another box is always configured manually to 192.168.0.10, so is outside any dynamic range. Some of the firewall rules on the router are set to send certain ports to 192.168.0.10

Quote from: garyw

The router dynamic IP range is 64-253 and I'm using 44 so that shouldn't be a problem.

Agreed. That looks OK.

Quote from: garyw

I think the router must have firmware specific to Plusnet because all my details are preconfigured and I'm unable to edit them, I can't even edit the router DNS settings!

That's new to me, but then I don't have a PN-supplied router.

Quote from: garyw

One thing that I’m not sure about is an option called ‘Auto-IP Enabled’ in the router settings. It’s currently unchecked but there is no mention in the router help files about what this does and no amount of googling has turned up an answer. See here – http://s134415674.websitehome.co.uk/router.jpg

No idea either, but I do see something strange... your router seems to have an IP of 10.0.0.138 allocated too. Looks strange to me...

[#10]

Quote from: garyw

I tried WWWombat’s suggestion of setting the DNS of the static IP on the PC to 192.164.1.254 to let the router worry about where to send requests. That got the static IP working fine and without the DNS issues I was having before. So far so good. But despite setting up port forwarding on the router to the new fixed IP my PF Port Checker app was still saying that the ports were closed on my PC. I tried rebooting PC and router but to no avail. Then I found a setting hidden away in the router admin control panel on each connected device that ensures that each MAC address is always assigned the same IP address. So as per WWWombat’s original suggestion I ditched the fixed IP on my PC and reverted to dynamic IP but ensured that the router assigned my PC with the same IP every time. I then set up the port forwarding again to the new fixed IP. That all worked fine. So far so good.

That sounds the right thing. Does it all still work with the PCs set to get both IP address dynamically *and* the DNS address dynamically?

Quote from: garyw

I tried PF Port Checker and port 13377 was open on TCP and UDP, all good. However, 12327 was open on TCP but closed on UDP. I went back and double checked the port forward setting but UDP on port 12327 is definitely forwarded to my PC. Cue a slight sigh and scratch of head. So I checked again half an hour and a couple of reboots later. IP address unchanged as expected but now port 12327 is closed on TCP and UDP, and port 13377 is closed on TCP but still open on UDP. What the F...!! Nothing has changed and I’m now getting different results. The application that uses 12327 now won’t even connect. I’m at a complete loss as to what is going on here unless this is a traffic shaping issue but I’m on the Pro package which supposed to have little or no traffic shaping applied.

No specific ideas that solve the problem, which does indeed sound strange. I guess the first thing to check is whether the "closed" ports are reported that way because thet are closed on the router, or closed on the PC.
You could run something like Wireshark on the PC while the port-checker runs. If the router is open, you should see packets arrive at the PC at least.
Otherwise I wonder if your internal application is using UPnP to get the router to open the ports, and this is interfering with your fixed configuration.

[#11]

Quote from: WWWombat

That sounds the right thing. Does it all still work with the PCs set to get both IP address dynamically *and* the DNS address dynamically?

Yep I'm getting IP and DNS dynamically but IPs are fixed on the router so each device always gets the same IP. That's for all devices that connect to my router - several computers and two iphones - and it's all working fine.

Quote from: WWWombat

No specific ideas that solve the problem, which does indeed sound strange. I guess the first thing to check is whether the "closed" ports are reported that way because thet are closed on the router, or closed on the PC. You could run something like Wireshark on the PC while the port-checker runs. If the router is open, you should see packets arrive at the PC at least. Otherwise I wonder if your internal application is using UPnP to get the router to open the ports, and this is interfering with your fixed configuration.

Thanks.
I had a play about with UPnP settings on the router and the applications but to no avail.
I tried Wireshark with PFPortChecker and the packets are definitely not getting to my PC.
Bizarrely though I switched on my PC today and tried to run one of the applications that requires port forwarding (Soulseek) and it ran fine for a few minutes. Then all of a sudden I couldn't browse the web and soon after that Soulseek starts grinding to a halt too. I had to reboot my PC and when I did internet connectivity was fine but Soulseek wouldn't connect and ports were reporting as closed again. Wierd!?
I've contacted plusnet support as this problem seems to defy all logic.

[#12]

Have you tried the "Soulseek Server and Client port connection test" http://daelstorm.thegraveyard.org/scripts/slsktest.php
Your problem sounds like the firewall on your Windows PC is misconfigured,  if you have a firewall enabled on your router then try temporarily disabling the Windows firewall - and see if the problem goes away.
What port numbers and which protocols have you got forwarded (for "Soulseek") in your router configuration ?

[#13]

Quote from: purleigh

Have you tried the "Soulseek Server and Client port connection test" http://daelstorm.thegraveyard.org/scripts/slsktest.php

Its saying my client port is inaccessible but that's to be expected since that's the problem I'm trying to fix. No? I've already tested the port using the application itself and PFPortChecker / Wireshark on my PC and it's definitely inaccessible.

Quote from: purleigh

Your problem sounds like the firewall on your Windows PC is misconfigured,  if you have a firewall enabled on your router then try temporarily disabling the Windows firewall - and see if the problem goes away.

Thanks for the suggestion but that was the first thing I checked. I've tried with Windows firewall on and off, it makes no difference.

Quote from: purleigh

What port numbers and which protocols have you got forwarded (for "Soulseek") in your router configuration ?

Soulseek chooses a random listening port in my case it's 12327. Here's the portforward.com page for Soulseek and my router - http://portforward.com/english/routers/port_forwarding/Thomson-Alcatel/TG585v8/Soulseek.htm
I've forwarded port 12327 on UDP and TCP to my PC which is called Tom-Acer-PC on my router.
Here's my router config -

Game and application sharing config on router
Port forward set up on router screegrab 1
Port forward set up on router screengrab 2
PC config on router

[#14]

This kind of behaviour (random ports, and manual reconfiguration of the router) is exactly what uPnP is supposed to stop.
According to this page, you should try turning uPnP on in the router (your screenshot says it already is) & in Soulseek:

Quote

3: turn on uPnP in soulseek options. Options/General Options/Use uPnP (automatic port forwarding) put a tick in the box next to this option

and take away the manual configuration.

[#15]

Quote from: WWWombat

This kind of behaviour (random ports, and manual reconfiguration of the router) is exactly what uPnP is supposed to stop. According to this page, you should try turning uPnP on in the router (your screenshot says it already is) & in Soulseek: Quote 3: turn on uPnP in soulseek options. Options/General Options/Use uPnP (automatic port forwarding) put a tick in the box next to this option and take away the manual configuration.

Thanks. I tried that already, same problem, and thinking about it I've used Soulseek for years on many different ISPs and routers and I've never had a problem using uPnP and port forwarding at the same time
I'm convinced this is something to do with my recent change from the old Plusnet Pro package to Plusnet Extra with Pro add on. The reason I say that is that I've now noticed that I can't use FTP / SFTP, I can connect sometimes, but as soon as I try to do anything (upload /download) my connection keeps timing out. All my FTP connections are preconfigured in winscp and I know they're definitely working because I can still access from work. This is a very recent problem, FTP / SFTP was fine a couple of weeks ago, and the only thing that has changed is my Plusnet broadband package. General Internet connectivity is fine (web and email) but I suspect FTP and peer-to-peer is being blocked by Plusnet.