September 25th, 2003, 03:34 PM
ports in windows XP
I think M$ blocked unassigned ports in winXP. f2f works on 60666 (i like 6's and it's unassigned), but I can't connect to someone with XP, while on 98/2000/ME it works.
Do you think ports are blocked? Can it be done by the system?
September 25th, 2003, 03:40 PM
try netstat -an and see what is listening. more likely they are behind a firewall or a router doing NAT, read this thread for more info: client server apps across the net
September 25th, 2003, 04:02 PM
Or maybe DSL could be the problem - both of friends with XP have DSL...
I read the entire thread, but I understood nothing but the coffe-cup :D
September 25th, 2003, 04:16 PM
I doubt that DSL would be the problem. I have been fortunate enough to avoid XP (except for in a couple classes), but I do run Win2000 at home, which is supposed to be very similar but not as ugly.
I've had some problems with Win2k wanting to authenticate my WinME laptop before it would let it connect, so I've always worked the drive mapping and file transfer from the Win2k box. Windows of the NT persuasion (NT/2k/XP) is much more security-minded and restricts access, whereas Windows 95/98/ME is downright promiscuous by allowing access to anybody.
In addition, I understand that XP comes with a built-in software firewall, so it could very well be blocking ports.
September 25th, 2003, 10:39 PM
Have you disabled MS Auto Update? If not, then they have probably updated your machine to turn on most security 'features'. They got a tremendous amount of flack for releasing their default installations with security holes big enough that you can drive several semi's side by side. I recall reading an NTBugTraq post after the latest round of the worm that fed off the RPC buffer overflow that they were going to change their update to start to configure people's machines to have more security (I run Win2K with auto-update off, so haven't tested whether it is true). It is possible, particularlly since XP is now their 'flagship' product, that they are doing something 'helpful' to you and/or your friends and how the firewall is on and blocking what you are trying to do.
September 26th, 2003, 09:42 AM
Is there a way to discover which ports are blocked?
Or can I use one already used, for instance #20?
I don't think this could be such a great catastrophe - you know, quake servers run on unassigned ports (27960-27975)!
September 26th, 2003, 10:12 AM
I imagine that XP has a way to tell you what ports are blocked, but I have no idea. I am studying on how to design my own (Win2K) firewall because I can't figure out how to use any of the ones that are freely available. It seems like a simple thing to me, but perhaps it is the typical software bloat that is getting in the way. I installed Symantec's firewall on a machine once and the damn thing wouldn't let me use the CD burner! I am hoping that once I have written one of my own I will be able to extrapolate that knowledge to how to use the commercial ones, but all my reading so far does not indicate how turning on a firewall would keep my CD burner from doing its job.
September 26th, 2003, 10:16 AM
I'll simply use port 20. Is that OK?
September 26th, 2003, 10:19 AM
As I understand your problem, you are having problems getting your friends to accept your connections. Changing your port won't solve your problem unless it is a port that is not being blocked at their end. Try a port almost guarenteed to be unblocked, such as 80 (HTTP) and see what happens. Generally, firewalls will block a port unless specifically told not to (pretty worthless if the default is to allow, but some are like that).
September 26th, 2003, 10:55 AM
September 26th, 2003, 11:05 AM
Then you are being blocked by something on your own side. You can run netstat -an (from a CMD prompt) to find out what processes are already listening on which ports (you are writing a server, right?), and I believe XP has an additional flag that will tell you which processes are on which ports. You must be logged on an administrator to connect to low-level (sub 1024) ports. Based on your error, I would speculate you have a firewall blocking the connection. See if you can connect to 127.0.0.1 (the loopback address) and see what happens. Do you have any servers you know run (such as Apache)?
September 26th, 2003, 11:18 AM
I have win98 and no firewall, so i can connect to localhost - the one who runs the server is on XP - server retrieve it's IP address OK, but when I want to connect it doesn't work. My port is 60666, not low-lever or whatever.
September 26th, 2003, 11:26 AM
OK, let me get this strait. Are running a client or a server? If you are running a client, you are connecting to the XP machine and must supply the XP machine's IP address. If you are running the server, the XP machine is trying to connect to you, you don't supply an IP address (unless you want the server to only bind to a single NIC if you have multiple NICs). Can you ping each other? If you can't ping each other, you may have larger problems (or have ping turned off, dunno the default on XP or 98, it is on for Win2K). I believe that XP has a telnet server that can be activated via services (don't leave it on!), try to telnet to the XP machine and see if you get a prompt. If you can't get the two machines to acknowledge one another, you have to resolve that before you try to get your own code working.
September 26th, 2003, 11:30 AM
I run the server and (try) to connect to XP machine. I connect to it via IP, not name.
September 26th, 2003, 11:35 AM
If you are running a server you do NOT try to connect to the XP machine, it trys to connect to you.
Are you sure you know what you are trying to do?