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Strange Networking problem

smartcooky said:
As I said in the note, the computer spent long time on the black boot screen, with lots of text popping up that tbh, I didn't take a lot of notice of. I did check the Device Manager and there were no exclamation marks warning me about unknown hardware.

These computers don't have Network Interface Cards, they have Network Adapters built into the motherboard (I presume that's what you mean). I will try going into Device Manager, uninstalling the Realtec Network Adapter, then "Scan for hardware changes" and see what happens.

UPDATE: Ok, I did that. The Network Adapter reinstalled correctly, the physical addresses listed in ARP -A are unchanged, and it hasn't fixed the problem
Click to expand...

Yeah, the Ethernet adapter on the motherboard is a NIC and will have its own MAC. I think you must be right that the system recognized and loaded the drivers for it during that first power up. Well, it was worth a try, although I hope I didn't cause you to waste a bunch of time.

The ipconfig results you show are from when you manually assign the IP, correct? What does the IP config show when you use DHCP? And what are the IPv4 addresses for the DNS server is both cases. (You may have posted these, but I'm about half brain dead today.)
 
One thing I like to do in cases like this is test the computer on a Linux distribution to see if the problem repeats itself there. If it does, it's a network issue that probably requires poking around your internet gateway to see if something's amiss. If it works great under Linux, then the problem's in Windows and you need look at things on the local computer.

I really doubt what follows is your problem (because your IP addresses are static) but one time I had a mainboard that would get a different IP address every time I restarted it, despite my DHCP server being set up to hold the lease. It turns out the two least significant bits of the first byte of the MAC address have special uses. One of them was set in such a way that caused my DHCP server to ignore its previously assigned IP address and hand out a new one. I got a fix from the mainboard supplier to change the MAC address ... I had to boot DOS from from a floppy to apply it!
 
JimOfAllTrades said:
Yeah, the Ethernet adapter on the motherboard is a NIC and will have its own MAC. I think you must be right that the system recognized and loaded the drivers for it during that first power up. Well, it was worth a try, although I hope I didn't cause you to waste a bunch of time.
Click to expand...

I consider any time spent doing things that didn't work a learning experience... (think Edison and light bulb filaments)

JimOfAllTrades said:
The ipconfig results you show are from when you manually assign the IP, correct? What does the IP config show when you use DHCP? And what are the IPv4 addresses for the DNS server is both cases. (You may have posted these, but I'm about half brain dead today.)
Click to expand...

When I allow the DHCP to choose the IP address, say 192.168.1.12 that IP address shows up when I do IPCONFIG. If I then go to any other computer and do ARP -A, that IP address appears in the list of network IPs. This is why I think making a shortcut with a target of \\IPADDRESS works when \\COMPUTERNAME does not.
 
Blue Mountain said:
One thing I like to do in cases like this is test the computer on a Linux distribution to see if the problem repeats itself there. If it does, it's a network issue that probably requires poking around your internet gateway to see if something's amiss. If it works great under Linux, then the problem's in Windows and you need look at things on the local computer.

I really doubt what follows is your problem (because your IP addresses are static) but one time I had a mainboard that would get a different IP address every time I restarted it, despite my DHCP server being set up to hold the lease. It turns out the two least significant bits of the first byte of the MAC address have special uses. One of them was set in such a way that caused my DHCP server to ignore its previously assigned IP address and hand out a new one. I got a fix from the mainboard supplier to change the MAC address ... I had to boot DOS from from a floppy to apply it!
Click to expand...

When DHCP chooses an IP number, it remains the same through multiple reboots (heaven knows I've done enough reboots with this bloody thing to be sure of this).

However, when I have used the troubleshooter and applied the fix for the error "DHCP is not enabled for Ethernet 2", which I have done several times, it assigns a different IP address each time.
 
Ahh, this may be a network type issue, especially when you said it won't connect via the netbios name.

I'm assuming Win10? Go to Start->Settings->Network & Internet->Ethernet

That should give a list of the networks defined, which should just be one. Click on that, and it should bring up a network properties screen.

The first section should be "Network Profile". Make sure that's set to "Private"...if it's set to Public, it blocks a lot of NetBIOS and other traffic (like file and print sharing)...and that may be causing some issues. May not be the whole of it, but worth checking.
 
Hellbound said:
Ahh, this may be a network type issue, especially when you said it won't connect via the netbios name.

I'm assuming Win10? Go to Start->Settings->Network & Internet->Ethernet

That should give a list of the networks defined, which should just be one. Click on that, and it should bring up a network properties screen.

The first section should be "Network Profile". Make sure that's set to "Private"...if it's set to Public, it blocks a lot of NetBIOS and other traffic (like file and print sharing)...and that may be causing some issues. May not be the whole of it, but worth checking.
Click to expand...

It is set to Private
 
Modern devices like cell phones, tablets and laptops will create random MAC addresses when they connect to networks. This is a privacy issue, designed to prevent tracking. Old desktop computers with an Ethernet adapter will not have this ability.

Have you compared the MAC address associated with the static and dynamic IP addresses for your new computer? They should be the same.

If they are not the same, it probably means that the static IP is using the MAC address of the old computer, while the dynamic IP is using the MAC address of the new computer. If that is the case, it is a simple matter of replacing the old MAC address with the new one.
 
a_unique_person said:
Try a tracert from one that works, compare the result to the one that doesn't.
Click to expand...

Tracert Photolab-2
Unable to resolve target system name Photolab-2


Tracert 192.168.1.65
Tracing route to Photolab-2 [192.168.1.65]
over a maximum of 30 hops:

1 1 ms 1 ms 4 ms Photolab-2 [192.168.1.65]

Trace complete.
​

This is a similar result to what I was getting earlier... the IP address connects to the computer, the computer name does not, although interestingly, when I tracert the IP address, it shows the correct computer name. Curious!
 
BrettM said:
Modern devices like cell phones, tablets and laptops will create random MAC addresses when they connect to networks. This is a privacy issue, designed to prevent tracking. Old desktop computers with an Ethernet adapter will not have this ability.

Have you compared the MAC address associated with the static and dynamic IP addresses for your new computer? They should be the same.

If they are not the same, it probably means that the static IP is using the MAC address of the old computer, while the dynamic IP is using the MAC address of the new computer. If that is the case, it is a simple matter of replacing the old MAC address with the new one.
Click to expand...

see JimOfAllTrades reply to my earlier reply to your post

http://www.internationalskeptics.com/forums/showpost.php?p=14061963&postcount=19

"The MAC address table in the router has the same entries as the physical addresses listed in ARP -A"
 
smartcooky said:
Tracert Photolab-2
Unable to resolve target system name Photolab-2


Tracert 192.168.1.65
Tracing route to Photolab-2 [192.168.1.65]
over a maximum of 30 hops:

1 1 ms 1 ms 4 ms Photolab-2 [192.168.1.65]

Trace complete.
​

This is a similar result to what I was getting earlier... the IP address connects to the computer, the computer name does not, although interestingly, when I tracert the IP address, it shows the correct computer name. Curious!
Click to expand...

From memory so beware, dsn lookup is failing but reverse DNS lookup (ie name from IP address) works. There are different DNS record types used by the 2. Sorry on phone with small screen so hard to read some websites.
 
This is painful to read.

Firstly, you do not need to manually set the IP address to keep it fixed. The DHCP server (which will be in your router/modem) can reserve IP addresses for specific MAC addresses. My hypothesis is that this is the case on your network, but it's just a guess.

With network problems, it is important to diagnose exactly where in the connectivity chain everything breaks. I always start from the lowest level and work up.

The lowest level is "is the cable plugged in?" (Don't laugh, I've seen people trying to diagnose networking issues with the cable not plugged in.) We can skip that in your case because it obviously is plugged in.

Next, you need to check basic connectivity. Set the IP address to the desired one and do the following:

1. From a machine that is working, ping another working machine. i.e. open a terminal and ping the other machine's IP address.

2. From the same working machine, ping Google's DNS server on 8.8.8.8.

The above two steps just serve to verify that the router is not blocking ICMP packets (these are the packets that are used for ping and trace route). If the above tests don't work, you need to enable ICMP on the router.

Set the desired IP address and gateway on your new machine.

3. Ping your new machine from a working machine.

4. Ping the working machine from your new machine.

5. Ping the gateway from your new machine.

From what you've said above, I would expect all of these tests to work, but do them anyway. Assuming they do pass:

6. Ping 8.8.8.8 from your new machine.

If this works, your issue is DNS. If it doesn't work, your router is blocking access to the internet for that IP address / MAC address combination.

Assuming it doesn't work

7. Assign your new machine a different fixed IP address. Repeat steps 4, 5 and 6.

If it now works then definitely, your router permanently associates the correct IP address with the old MAC address. There will be a setting somewhere that will allow you to fix it.

If 7 works you might consider leaving it at that, but you will then have to change all the hosts files on that machine and the other machines as well as possibly updating the lmhosts file. Netbios names such as used in Windows file sharing use a different name resolution protocol to DNS.
 
jeremyp said:
This is painful to read.

Firstly, you do not need to manually set the IP address to keep it fixed. The DHCP server (which will be in your router/modem) can reserve IP addresses for specific MAC addresses. My hypothesis is that this is the case on your network, but it's just a guess.

With network problems, it is important to diagnose exactly where in the connectivity chain everything breaks. I always start from the lowest level and work up.

The lowest level is "is the cable plugged in?" (Don't laugh, I've seen people trying to diagnose networking issues with the cable not plugged in.) We can skip that in your case because it obviously is plugged in.

Next, you need to check basic connectivity. Set the IP address to the desired one and do the following:

1. From a machine that is working, ping another working machine. i.e. open a terminal and ping the other machine's IP address.

2. From the same working machine, ping Google's DNS server on 8.8.8.8.

The above two steps just serve to verify that the router is not blocking ICMP packets (these are the packets that are used for ping and trace route). If the above tests don't work, you need to enable ICMP on the router.

Set the desired IP address and gateway on your new machine.

3. Ping your new machine from a working machine.

4. Ping the working machine from your new machine.

5. Ping the gateway from your new machine.

From what you've said above, I would expect all of these tests to work, but do them anyway. Assuming they do pass:

6. Ping 8.8.8.8 from your new machine.

If this works, your issue is DNS. If it doesn't work, your router is blocking access to the internet for that IP address / MAC address combination.

Assuming it doesn't work

7. Assign your new machine a different fixed IP address. Repeat steps 4, 5 and 6.
Click to expand...

All of these steps were done before I even posted here, except I pinged 1.1.1.1 instead of 8.8.8.8 (Cloudflare instead of Google), so we are really way beyond any of this.

One of the main points here is that the replacement computer can connect to all the other computers just fine, that is, we can navigate to every other computer, and use all the network devices such as printers and scanners, from the replacement computer. Its just that we cannot navigate to the replacement computer from any other computer when the DHCP chooses its own IP address, and when we have the IP address fixed, the replacement computer is booted off the internet.
 
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You could try swapping the computers around. It might provide more insight into the problem you are experiencing.
 
The directory service that routes requests to each of the computers by name doesn't know enough about this computer to route requests to it. It's been a while since I've done any serious network troubleshooting, and I'm not about to start now, but this is probably WINS or something. Giving it a routable IP address won't fix the problem with the name-based routing registry. Basically it sounds like you've done everything right except the part where Windows machines talk to each other as Windows machines rather than as arbitrary IPv4 endpoints.
 
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smartcooky said:
All of these steps were done before I even posted here, except I pinged 1.1.1.1 instead of 8.8.8.8 (Cloudflare instead of Google), so we are really way beyond any of this.
Click to expand...

The worst part of IT troubleshooting is end-users getting pissy when you start with the basics because you have no idea what they've already tried or what the results were.

"Trust that I've already tried the obvious stuff. What else could be going wrong?" is a terrible strategy for getting tech support.
 
smartcooky said:
All of these steps were done before I even posted here, except I pinged 1.1.1.1 instead of 8.8.8.8 (Cloudflare instead of Google), so we are really way beyond any of this. ...
Click to expand...

Just to clarify, when assigned its fixed IP address, the new computer could not ping 1,1,1,1?

And when DHCP gave it another IP address, the other computers on the network could not communicate with it by its computer name, but they could by its IP address?
 
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