Cannot X-Windows to another subnet

[Veron Le_1]

hi,

We have some subnet:
x.x.20.x; x.x.21.x; x.x.103.x with mask: 255.255.255.0
My PC is on x.x.103.x, I CAN use X-Windows to connect to x.x.20.x, and I CANNOT use X-Windows to connect x.x.21.x. However I CAN use X-Windows to connect x.x.21.x from PC on the same subnet.

The question is why I only can using X-Windows on the same subnet Once I cannot when on the different subnet????

Appreciate your soon response.
Thanks very much.
TLC

[Bill McNAMARA_1]

Xwindows discusses over tcp port 6000. Make sure that there is no firewalling or routing problems.

[Veron Le_1]

I discussed with network management, they confirm that all port are opened, any no firewall using.

Thanks for you quick response.

[Victor BERRIDGE]

Hi,
Just some thoughts...
Are you sure of the netmask at x.x.20.x and more specifically x.x.21.x It could look like a 255.255.252.0 having the same gateway for both (which is correct)...

All the best
Victor

[Ravi_8]

Hi,

can u make network FD(full duplex) on both ends and give a try

[Massimo Bianchi]

Hi,
just another hint: are routes configured in the same manner, from x.21.x and x.20.x ?

May be they go throught different path.

Also: do you allow connection from all hosts ?

HTH,
Massimo

[Hai Nguyen_1]

Trung,

Your routing may not be correct.

Can you ping the server on x.x.21.x from your x.x.103.x PC?

One option is when you open an x-sesssion to x.x.20.x from your 103 subnet, telnet to x.x.21.x from the x-session.

Hai

[Ian Hillier]

We use Exceed here and had the same situation. There's a file called xdmcp.txt that I had to populate with the subnets I need access to.

192.168.101.255
192.168.110.255

You can also put individual addresses in there, but putting the .255 address covers all xhosts in that subnet.

I think these files/conventions are standard so whatever program you're using should have the same type of config file.

Regards,

John

[John Dvorchak]

It really sounds to me like the system on x.x.21.x either has the wrong netmask or it's default gateway is nonexistant or incorrect.

From the 103 box ping or traceroute to the 21 box and see if you get returns. My guess is that it will fail. If it fails contact the admin on the 21 box to verify his netmask and default router/gateway settings are correct.

[George Liu_2]

Your network setting has a problem, or security stuff not just firewall, may be tcp-wrapper, is functioning. Try telnet remoteIP 6000 to test X port is accessible first.