Hi, My network : Isa : Lan - 192.168.37.2 subnet - 255.255.255.0 Dns - 192.168.37.2 Wan - 200.173.218.146 subnet - 255.255.255.248 dns - 200.225.83.10 The users in network use smtp.mandic.com.br and imap.mandic.com.br, but, when ISA Firewall is started all users receive error messages .... what can I do ?