We can't browse internet unless we changed our gateway ip. How to solve this problem ? Is it a gateway problem or router problem ? I've contact our ISP to check our router and modem, both are ok.We're using leased line and running on Win NT 4.0 and Ms.Exchange 5.0 as email server.Is it possible cause by virus ?

What are you changing your Gateway from/to? Did your ISP give you the IP addresses? If so, use the ones they gave you.

You say you cant BROWSE But is there contact with the internet. Try this please In a dos box Ping your local gateway computer( the computer on your network that makes connection to the net) ping a computer on the net by its IP ADDRESS !! e.g. ping 194.109.6.44 this is an ISP here in the Netherlands and is always on If you can't ping this compu; the connection to the net is not good or your firewall/router does not permit it If you can than try ping microsoft.com Íf there is no IP resolution than the DNS does not work. This means your PC can't resolve the IP address belonging to the name microsoft.com Common failure ! If you check your IP stetting you wil find a tab where you can fill in a DNS server Fill in 231.48.253.16 (this the DNS server from XS4all but that doesn't matter Now you have to be able to browse the net. You can go to the page of your ISP to change the DNS in theirs. HOWEVER If you're network also has a DNS server you should enter the IP Address of this external DNS server in the list of IP addresses on your network DNS server If this is to confussing you can email me direct and we can do it step by step. I caneven do some portscans on your router if youlike etc etc Whatever you want. Email me direct if you ned the assistance Succes Succes