for ILL connection My ISP gives me for wan link ip x.y.238.214 subnet 255.255.255.252 with a gateway x.y.238.213 also gives me a global ip pool x.y.239.120 subnet 255.255.255.248 for acceesing.
Previously there was a configured router which i now to replace by a dual lan card server.
I already setup zeroshell where ETH01 IS SET TO x.y.238.214 subnet 255.255.255.252 for wan link with a gateway x.y.238.213 AND ETH00 IS SET to x.y.239.121 subnet 255.255.255.248 for which from the computers of global ip can acess internet but reverse is not possible.
Please send me a zeroshell step by step configuration so that All computers of global ip pool can be directly access from the internet world
I have not so much knowledge to write ip routing myself.
You should not use NAT in ZS. If your clients in the internal network use x.y.239.121 as the default gateway there is nothing else to do. Most like the problem is that the ISP is not advertising the /29 subnet that he has allocated you, or is expecting from you to advertise it via RIP or OSPF.
A quick way to check is to try and traceroute from the ZS a public server such as http://www.yahoo.com and then try the same from a internal PC. If the traceroute stops at the ZS then most likely it is a problem of your ISP not returing the traffic back to you.