help on network config

[Nils Kassube]

stin wang wrote:
> pc1
> ip 172.18.20.87
> mask 255.255.255.224
> gate 172.18.20.94
> pc2
> 172.18.20.98
> 255.255.255.224
> 172.18.20.126
> pc3
> 172.18.20.225
> 255.255.255.224
> 172.18.20.253
>
> i can ping 172.18.20.98 172.18.20.225 in pc1 ,it's ok
> but i can't use ftp,vnc,or tsclient to pc2 or pc3, but it's ok for
> 172.18.20.88 which is in the same gateway as pc1,

How are those PCs connected? There should be a router with 3 ports between 
the PCs with the addresses *.94, *.126 and *.253 and it needs routing 
enabled between the ports.

> or just ubuntu have some problem with subnet??

Don't think so. Probably there is something wrong with your network 
layout. If all 3 PCs should see each other, you should better use the 
same subnet for all of them. E.g. PC1 = 172.18.20.87, PC2 = 172.18.20.88, 
PC3 = 172.18.20.89, netmask 255.255.255.224. If you have a router 
connecting your network to the internet, use the IP of the router for the 
gateway on all 3 PCs.

However, if you have a router connected, it is highly recommended to get 
rid of your static routing. Enable DHCP on the router and on the PCs.


Nils