Greetings, Let me give you more info about the settings: - The LAN interface has the following TCP/IP 192.168.15.1 / 24 and default gateway the same. - The WAN interface has the following TCP/IP 66.207.210.90 / 29, default gateway 66.207.210.90, DNS 66.207.192.4 The ISA server is used to connect a web / ftp server to the internet and to receive external e-mails on an internal Exchange server. It's not used as a proxy. The problem is that on average once a day , trying to connect from internet to web / ftp is not working and the e-mails are not received on the Exchange. The test I run is to ping from the ISA server the external dns, 66.207.192.4 and there is no reply. I can ping 66.207.210.89, the gateway interface. The workaround is to do ping 66.207.192.4 -t disconnect the LAN interface patch cord, and watch the screen. In about 5 - 10 seconds there is a reply and can connect the patch cord to the hub again. Everything work fine from that moment. If you have any suggestions I would appreciate them. Regards, Adrian