Network issues

[Glirk Dient]

For some reason nobody can connect to eachother on a network. We also cannot host servers that anyone can join(in or out of the network). Joining outside servers is just fine, as is much anything going out.

I have enabled pretty much every port I have seen come up and still nothing, I have taken myself out of the DMZ and still nothing, people on my network cannot join the server. I have a linksys router and a switch with which everything is plugged into. We have tried programs that create an external server and still that does not work. Something seems to be hindering the computers from talking to eachother. On top of that we periodically get disconnected from any internet activity for a few minutes. Any ideas?

[ober]

We'll need more specs: OSes used, routers/hubs, and you'll need to tell us if anyone is running a firewall or not.

[Waldo2k2]

bring down windows (or other software) firewall
kill programs like "norton internet security"

opening all ports permanently is a bad idea. Also, the DMZ (de-militarized zone) means that any computer currently in the DMZ will have access to all internal and external ports so that should have worked. By opening ports I assume you used port forwarding, forwarding all ports is a bad idea, this can create loopbacks in your network that you didn't intend to create (which would cause the internet flakiness). Since you're behind a router, software firewalls should be off. Open only what ports you need to on the router (set the forwarding destination ip to 192.168.0.0 assuming 192.168.0 is the subnet you're in). If that doesn't work, remove port forwarding and put the computers in the DMZ and check if that works. If that doesn't work, something is whacky with your computers. At that point it would be best to just plug them into the switch, give them static ip's, and see what happens. If nothing works then, well, you're probably using crossover cables instead of standard cat5. Let me know if you didn't understand any of that.

[Glirk Dient]

I understand it, we tried the switch, same thing. Only one comp can go in the DMZ at a time, so that didn't work. All of them are cat5.

EDIT: Here is a post I made on another forums, it details everything I have done up until now.

I have 2 computers that I am trying to setup a network for. All we want to do is be able to connect to one anothers server for a game, however it just fails. We are normalls on a switch that is plugged into a router. I first thought it was a router issue, but we made a crossover cable and that failed the same way. We have run the network wizard on both computers, disabled all AV and firewalls, XP included. Both computer have Windows XP, and both can access the outside internet through the switch/router.

We have tried a program that will create an outside server for us to connect to eachother directly through, that did not work. We cannot see eachother at all on the network, nor can we ping. Sometimes I will be able to ping the other computer, but that is random and he can never seem to ping me. I have been trying for over 7 hours now to get this fixed, and it has always been a problem. Anyone have any suggestions?

[Waldo2k2]

Are you sure that you are both in the same subnet? Are you in the same workgroup? Do you have sp2 installed?

[MisterSako]

i just recently had fixed my network upon replacing my router. its a big pain in the @$$

one important thing you need ot make sure of is the prefix of your IPs are the same.

for instance the router might be
123.123.0.1

and one computer might be
123.123.0.2

and the other is
123.123.0.3

i think thats the subnet thing that waldo was talking about..

make sure when you did the wizard setup you selected the right kind of network your settnig up

[Waldo2k2]

>>i think thats the subnet thing that waldo was talking about..

that is correct.

I would suggest going back to that crossover, give one pc 192.168.0.1 and the other 192.168.0.2 and make sure the workgroup name is the same (right click my computer, properties, computer name) and see if you can ping eachother (start, run, cmd, ping 192.168.0.2 if you're on the .1 pc). If they can't ping then someone is running something that's blocking everything (or the cable is bad) but we know the straight-through cat5 and everyone's nic's are fine because you could get internet via the router. You can safely assume then that it is a software problem and someone either needs to completely reload the pc or dig through till you find the cause.