Could it be a hardware issue that ether1 cannot obtain an IP-address from the ISP through the Sagem F@ST 908 E2T? Every other interface gets the address within a second but the ether1 stays forever at state "searching". OS v. 5.2. there is no bridge interface installed.

If there could be something wrong with the configuration what shoud I check for?

Sometimes different hardware doesn't negotiate port speed/duplex properly. You could try manual settings.