Setting a fixed IP loses internet connection

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Hi,
I have this computer connected to a modem/router.
Whenever I set the internal IP of the PC to a fixed address, the internet connection is lost.
When I put it back to automatic it connects again.
Even when using the settings that are set by the router it doesn’t work.
Details for instance:
IP 192.168.1.20
Submask 255.255.255.0
Gateway 192.168.1.1
DNS1 192.168.1.1
No DNS2.

Other computers in this network have a fixed IP and internet connection.
Disabling the firewall doesn’t seem to matter.

Anyone?
TIA
Sjors

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Hi sjors,

These two statements you wrote seem to be contradictory, and I do not know what to make of them:
“When I put it back to automatic it connects again.
Even when using the settings that are set by the router it doesn’t work.” What settings are you referring to here?

The router is evidently set up to use DHCP to automatically supply IP addresses to the computers on the network. Otherwise when you set your PC to obtain an IP address automatically, it would not be able to connect.

On the router setup page there is an input field to specify the number of computers to allow automatic IP addresses, and there is a range of IP addresses that can be chosen to be supplied to those computers. For example, there might be 10 computers allowed on the network for DHCP to automatically assign IP addresses. Now, for example, on the range of IP addresses, let’s say the first one at the beginning of the range is set at 192.168.1.11 and the last address that can be assigned in the range is 192.168.1.20. If this were the range of IP addresses set for the 10 computers, then when you decide to set your computer up with a static IP address, you would need to choose an address outside of the reserved automatic range. Therefore you would avoid setting your static IP to any address starting at 192.168.1.11 thru 192.168.1.20. You could set your static address to any number besides these, for example, you could set up the address 192.168.1.10, or 192.168.1.21, or any number (after the third dot) lower or higher than these two. You cannot use any address that has been reserved as an automatically assigned address or you will get conflicts. The numbers I listed here are examples only. Your network could be set up with any number of IP addresses that have been reserved for use by DHCP. The other computers you mentioned that have static IP addresses and have no problem connecting probably have IP addresses that are outside the range that has been reserved for the router’s DHCP.

This could be the reason you cannot connect when you set a static IP address on your PC.

Another thing to check is to be sure the IP address you have chosen for your static IP conforms to the subnet mask you listed above, which is 255.255.255.0, which means in your case, the first three sets of digits must be 192.168.1. The fourth number is the only one that will be different from all others used in your networks’ IP addresses.

Hope this helps.

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Hi Gerald,
Tnx for this.
I’m aware of the concept you describe.
That’s why I gave this pc a fixed address outside the range (of 20 in my case).
Although your answer helped to check settings again, it doesn’t help to solve my problem I’m afraid.

tnx anyway,
Sjors

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Do you mind me asking why you do not want to use DHCP to assign IP addresses automatically? What is the compelling reason to go with a static IP address on your PC?

I use a static IP address on my network printer so all the computers on the network can reliably send print jobs to a fixed IP address rather than contend with one that changes every few days.

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Whenever I set the internal IP of the PC to a fixed address, the internet connection is lost.

You must have made a mistake when you set the address. As long as the netmask and DNS are correct it doesn’t matter what IP address you use, as long as it’s within the range and not .0 or .255.

cheers, Paul

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Hi both,

The reason of a fixed IP is to be able to get a remote connection to this pc (and others in the network).

Evidently I should have made a typo, but after checking it 10 times at least…
Having done this thousand of times it will still be possible of course, but I can’t find the typo.

What I mean with the settings by the router is the dhcp-thing in the concept you wrote.

tnx again,
Sjors

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What is your router make and model? What is your OS on the PC with the issue?

Since other PCs on your network have a static IP and work ok, the next thing to check is to see if TCP/IP is properly configured on the problem PC. While your computer is still set up with the static IP address, go to Command Prompt (CMD) and type: ping 127.0.0.1 and press enter to see if you can successfully ping your computer. If errors are returned, then TCP/IP is misconfigured and needs to be fixed.

Some routers give you the capability to set a static IP address for a specific computer (or several computers). Have you checked your router to see if it has that capability? If so, try to assign the static address from within the router instead of doing it on your PC.

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Hi Gerald,
tnx for staying with me
it’s a Fritz! 7270, I don’t think it’s on the US-market.
The OS is XPP latest patches.
The Fritz doesn’t have this capability, NEIN!
It’s German, from avm.de

I will check the settings again, but that might take some time before I get to this location.

Regards,
Sjors

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Even when using the settings that are set by the router it doesn’t work.

hmmm

I am going to assume by you saying this that you set the machine to DHCP (obtain an IP address automatically).

You then issued an IPCONFIG /ALL from the command prompt and wrote down all the information such as; subnet mask, gateway ip address, DNS servers, etc.

You then went in and ASSIGNED the information above setting the computer’s IP address outside of the range of DHCP lease range on your router.

If you have done as above, about the only thing it can be is a duplicate IP address on your network. From another machine (or from this machine while it is still in DHCP mode) PING the address you wish to assign to be sure it is not already in use. If it is you will need to change the IP on the other device or use a different IP for this computer.

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Hi Mercy,
Yes, you are correct, this is the way I handled things.
And checked over and over again.
Next week I will do it again (done this the last 20 yrs on hundreds of machines though).
Nevertheless, as you all say I must have made some mistake.
Will let you folks know.

tnx again,
Sjors

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Nevertheless, as you all say I must have made some mistake

I don’t know about that, did you ping the address first too be sure it is not already in use?

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Hi,
I always use an IP-scanner like the free one from famatech

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Does the router do some weird things with addresses that are not allowed out unless assigned by the router. or only NAT a specific range?

cheers, Paul

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No Paul, nothing of that kind.

thank you
Sjors

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Can you ping the machine from others on the network?

cheers, Paul

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Hey sjors,

Try this:

IP 192.168.1.20
Submask 255.255.255.0
Gateway 192.168.1.1
DNS1 ..can check at myipaddress.com or your router’s main page
DNS2 8.8.4.4

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Paul asks a very good question (one of the first that should have been asked)

Do you have connection to your network with the fixed IP and are only not able to browse the internet, or do you have no network connection at all when you assign the IP?

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Quite so, will try that next week, finding fixed and dhcp-ip through the network.
And yes, it’s only the internet that can’t be reached with a fixed IP!

Keep them suggestions coming, tnx.

Sjors

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And yes, it’s only the internet that can’t be reached with a fixed IP!

This eliminates a problem with duplicate IP or improper subnet mask. We are left with one of the following:

1. Improper gateway IP address> This has been checked and double checked

2. DNS setting problem> This can be tested by trying a PING http://WWW.GOOGLE.COM at the command prompt which I think will fail. If this fails, go to a working machine on your network and issue the same command. Write down the IP address of http://www.google.com that it shows. Go back to the non working machine and attempt to ping that IP address directly. If this works I would test with a DNS server entry from opendns (http://www.opendns.com). (Their dns server IP’s are in the lower right hand side of the page underneath the red OpenDNS logo).

3. Firewall rules that do not allow that address (or a range of addresses that include that address) to access the web. > To test this I would check that the highest numbered address in your DHCP range is free. I would then TEMPORARLY assign this machine that top address and see if it works. ( If your dhcp range is from xxx.xxx.xxx.100 – xxx.xxx.xxx.199, and xxx.xxx.xxx.199 is free, assign xxx.xxx.xxx.199 to this machine and see if it work.)

4. Something on your network that is not “standard” such as an internal proxy server, untangle filter, or smart switches and vlans.

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Here is what I would try.

Do these steps from a good PC and from the problem PC
First – ping the router > ping 192.168.1.1
Then – ping a website’s IP address such as google > ping 209.85.225.103
Then – ping the website > ping http://www.google.com

If you can’t ping the router, the network connection is not working at all.
If you can’t ping Google’s IP address, you have a router problem.
If you can’t ping Google.com, you have a DNS problem.

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Hang on to your hat. Your thread got featured in the Windows Secrets newsletter. You will soon have more suggestions then you could try in a week….

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I have found that repeatedly changing networking setups can ‘gum up’ the system. After changing settings, try first disabling, and then re-enabling the network adapter. Be sure to wait a bit for it to complete, as the visual cues aren’t that great. You can also try the repair option.

If that doesn’t work, try clearing the arpcache. From the DOS prompt, type “netsh interface ip delete arpcache” (no quotes)

If that errors, out, check if this system has MS’ Routing and Remote Access turned on. Turn this off, then clear the arpcache. If you need Routing and Remote Access, turn it back on.

Turn off Routing and Remote Services from the Admin console: under Administrative Tools, Computer Management, Services

If you don’t need that service, leave it off. You say you want the static IP for remote access, so you might need the service. You don’t specify the OS, so if it’s WinXPPro, SP3 disables it by default.

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I would try using the free trial of Network Magic. – http://www.purenetworks.com/download/

If it works, but you have to use it every time, your wireless adapter has probably developed an incurable fault.

In any case, if you have another wireless adpater, try using it.

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Ha, still thinking with me, tnx.
It’s not wireless, it’s ethernet.
Nevertheless, I had a chance today to look at the pc.
There seems to be working some special programm that is communicating with specific drivers to measure certain things like food-quantity and watertemperature.
It’s a fish breeding farm (for those interested: http://www.seafarm.nl).
It conflicts with internet-connections whithin a couple of hours when automatic IP etc is configured.
So that’s a nono for this pc, at least untill I have spoken to the ones responsible for this programm.
That means this topic will close for the moment, anyway from my part.
When I have other news I will let you all know on this forum.
Thanks again for your concern.

Regards,
Sjors

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Thanks for the feedback.

cheers, Paul

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Also don’t forget to flush the DNS cache. From a command prompt:

ipconfig /flushdns

You will use the ipconfig commands most often in troubleshooting, particularly ipconfig /all. I don’t use netsh unless something is very messed up.

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Hi David,
Just this morning I had a reaction of the Norwegian installer of this pc. He writes:
The pc was originally configured with a fixed IP, due to the wireless remote control unit.
This type of equipment responds very badly to dynamic/DHCP enabled networks.

That declares a lot, don’t you people think?

Sjors

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Is there a remote device the PC connects to?
Does their software and send directly from the NIC, rather than via Windows?
Nothing worse than badly behaved programs.

cheers, Paul

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