Lost ability to access Win10 from WinXP machine

phrab said:

tried nmap. I don't think I quite new how to use it, because I wasn't sure what target to specify.

Below is my attempt to clarify nmap's usage somewhat. I hope it helps.

My suggestion was to use nmap to find out what network ports are active on both computers and to find out if the computers' firewalls might be blocking any of those ports.

nmap itself is a command-line program. It should have been accompanied by the GUI interface program Zenmap. Zenmap's visual interface might be easier for you to use than nmap's command line interface. I used Zenmap for the examples below.

I'll assume your Win10 computer is at 192.168.0.10 and your XP computer is at 192.168.0.6.

To see the open ports of the WinXP computer, when you run Zenmap on either computer, you'd specify a "Target" of 192.168.0.6 (step 1 in the first attached picture), specify a "Profile" of "General Scan" (step 2), then click on the button "Scan" (step 3). Wait patiently for Zenmap's display to update. Sometimes it can be slow.

To see the open ports of the Win10 computer, you'd specify a target of 192.168.0.10.

On the computer where you run Zenmap, if you specify its own IP address as the Target, you'll see all of its active network ports. If you specify the IP address of the other computer, you'll only see the ports which are being let through the other computer's firewall. You can find out the intended use of each port by doing a Web search for
network port ####
where you replace #### by the actual port number.

Below are examples, showing what I see on a client (x) and on a media server (y). Both are running Win10.
Access to all of the client's ports are blocked by its local firewall. Its ports are visible only to itself and not to any other computer. None of the media server's active ports are blocked by the server's local firewall. Its ports are visible both to itself and to any other computer connected to the same local network.

ETA: Note that I accidentally wrote "services" instead of "ports" in the second pair of screengrabs.

selden said:

Below is my attempt to clarify nmap's usage somewhat. I hope it helps.

My suggestion was to use nmap to find out what network ports are active on both computers and to find out if the computers' firewalls might be blocking any of those ports.

nmap itself is a command-line program. It should have been accompanied by the GUI interface program Zenmap. Zenmap's visual interface might be easier for you to use than nmap's command line interface. I used Zenmap for the examples below.

I'll assume your Win10 computer is at 192.168.0.10 and your XP computer is at 192.168.0.6.

To see the open ports of the WinXP computer, when you run Zenmap on either computer, you'd specify a "Target" of 192.168.0.6 (step 1 in the first attached picture), specify a "Profile" of "General Scan" (step 2), then click on the button "Scan" (step 3). Wait patiently for Zenmap's display to update. Sometimes it can be slow.

To see the open ports of the Win10 computer, you'd specify a target of 192.168.0.10.

On the computer where you run Zenmap, if you specify its own IP address as the Target, you'll see all of its active network ports. If you specify the IP address of the other computer, you'll only see the ports which are being let through the other computer's firewall. You can find out the intended use of each port by doing a Web search for
network port ####
where you replace #### by the actual port number.

Below are examples, showing what I see on a client (x) and on a media server (y). Both are running Win10.
Access to all of the client's ports are blocked by its local firewall. Its ports are visible only to itself and not to any other computer. None of the media server's active ports are blocked by the server's local firewall. Its ports are visible both to itself and to any other computer connected to the same local network.

ETA: Note that I accidentally wrote "services" instead of "ports" in the second pair of screengrabs.

Thank you again for your reply. I had trouble finding my IP address & in searching for it, I found that I had no IPv6 address. I do now. I ran ipconfig /all in a command prompt. Before posting the results here, could you tell me whether I should post something like that online. If so, I'll post that & then run nmap.

Thank you again.

To be honest, I'd be reluctant to post that much detailed info about your network environment in public. Also, I don't know enough about Windows-specific networking to be able to provide help given that information, although maybe someone else could.

selden said:

To be honest, I'd be reluctant to post that much detailed info about your network environment in public. Also, I don't know enough about Windows-specific networking to be able to provide help given that information, although maybe someone else could.

Thanks again. I'll post a partial report that I ran on WinXP, but it looks very different than your examples:

XP Scan of it’s own ports
Starting Nmap 6.47 ( Nmap: the Network Mapper - Free Security Scanner ) at 2021-12-29 14:43 Pacific Standard Time

Skipping SYN Stealth Scan against i5sys.lan (192.168.X.XX) because Windows does not support scanning your own machine (localhost) this way.

Nmap scan report for i5sys.lan (192.168.X.XX)

Host is up.

PORT	STATE	SERVICE
1/tcp	unknown	tcpmux

I get 1,000 entries that look similar. Each says State = unknown. I haven't run it on Win10 yet. Does any of this make sense?

Also, I did check a box for IPv6, so the image above has changed to:

I used the Zenmap GUI front-end for nmap, so the screengrabs don't look identical to nmap's terminal output. Note that I'm using a much more recent version of nmap (7.91) than you are (6.47). I dunno if that might account for the differences you see. [It probably does.] I suggest you get a copy of the newest version directly from the nmap Web site (nmap.org).

Edited to add: Oops, sorry: I hadn't realized that 6.47 is the most recent version available for XP.
If it can't be used to scan a computer running XP from itself (which is what your error message claims), then "unknown" is to be expected for all of the ports that it tries to scan.

Running nmap in a Win10 terminal window does show similar info to what Zenmap shows. For example, here's what's shown when I run nmap on my media server to scan itself:

Code:

$ nmap 192.168.0.X
Starting Nmap 7.91 ( https://nmap.org ) at 2021-12-30 04:07 Ame
Nmap scan report for 192.168.0.X
Host is up (0.00034s latency).
Not shown: 992 closed ports
PORT      STATE SERVICE
22/tcp    open  ssh
135/tcp   open  msrpc
139/tcp   open  netbios-ssn
445/tcp   open  microsoft-ds
554/tcp   open  rtsp
2869/tcp  open  icslap
5357/tcp  open  wsdapi
10243/tcp open  unknown

Nmap done: 1 IP address (1 host up) scanned in 1.12 seconds

selden said:

I used the Zenmap GUI front-end for nmap, so the screengrabs don't look identical to nmap's terminal output. Note that I'm using a much more recent version of nmap (7.91) than you are (6.47). I dunno if that might account for the differences you see. [It probably does.] I suggest you get a copy of the newest version directly from the nmap Web site (nmap.org).

Edited to add: Oops, sorry: I hadn't realized that 6.47 is the most recent version available for XP.
If it can't be used to scan a computer running XP from itself (which is what your error message claims), then "unknown" is to be expected for all of the ports that it tries to scan.

Running nmap in a Win10 terminal window does show similar info to what Zenmap shows. For example, here's what's shown when I run nmap on my media server to scan itself:

Code:

$ nmap 192.168.0.X
Starting Nmap 7.91 ( https://nmap.org ) at 2021-12-30 04:07 Ame
Nmap scan report for 192.168.0.X
Host is up (0.00034s latency).
Not shown: 992 closed ports
PORT      STATE SERVICE
22/tcp    open  ssh
135/tcp   open  msrpc
139/tcp   open  netbios-ssn
445/tcp   open  microsoft-ds
554/tcp   open  rtsp
2869/tcp  open  icslap
5357/tcp  open  wsdapi
10243/tcp open  unknown

Nmap done: 1 IP address (1 host up) scanned in 1.12 seconds

Thank you again. I'm very confused. I looked at my firewall & turned it off (just for a few seconds). Then I tried to see if my shortcuts on XP would work to see Win , but they didn't. I turned the Win firewall back on, of course.

Would this experiment mean that it's not caused by any setting in the Win firewall? (really not sure what I'm doing, as this is way over my head).

Should I install & run ZenMap on my Win machine or would the above experiment mean that it's not a firewall problem?

phrab said:

Thank you again. I'm very confused. I looked at my firewall & turned it off (just for a few seconds). Then I tried to see if my shortcuts on XP would work to see Win , but they didn't. I turned the Win firewall back on, of course.

Would this experiment mean that it's not caused by any setting in the Win firewall? (really not sure what I'm doing, as this is way over my head).

You don't say on *which* computer you turned the firewall off.

If you turn the firewalls off on both computers at the same time and still have the problem, then yes, that indicates that the firewalls are not likely to be the underlying cause.

selden said:

You don't say on *which* computer you turned the firewall off.

If you turn the firewalls off on both computers at the same time and still have the problem, then yes, that indicates that the firewalls are not likely to be the underlying cause.

I just turned off all firewalls on both computers (WinXP has only 1 & Win10 has Domeain, Private, & Public). I switched to the XP machine, but the shortcuts to Win10 still don't work. I tried to map the Network drive from XP, but it doesn't see this Win10 machine. I did not reboot after turning off firewalls...don't know if that matters. I've turned the firewalls back on.

Unfortunately, I don't think I can help more than I have. The next thing that occurs to me would be to examine exactly what's happening on the network when the XP computer tries to communicate with the Win10 computer: what requests it sends and what (if anything) the Win10 computer sends back. Network monitoring software like Wireshark can be used to do that, but I have not the slightest idea what the network traffic should actually be. Sorry.

selden said:

Unfortunately, I don't think I can help more than I have. The next thing that occurs to me would be to examine exactly what's happening on the network when the XP computer tries to communicate with the Win10 computer: what requests it sends and what (if anything) the Win10 computer sends back. Network monitoring software like Wireshark can be used to do that, but I have not the slightest idea what the network traffic should actually be. Sorry.

Thank you for all your help & your time. I really appreciate it. I realize that I lost the ability after I used "Controlled Folder Access" & did an update on Win10. However, I removed the update & removed the Controlled Folder Access, so maybe there's something left over. I'll try to check it out. Anyhow, hope you had a very happy new year!!