Hi In exchange 2000 server we are using only smtp vserver to send and receive mails. In ISA firewall also we have enabled only smtp. Is POP3 is not necessary to receive mails? But while we are configuring any internet mail clients (outlook express, Eudora etc) we have to have specify SMTP and POP3 (or IMAP) server. I would like to know the role of SMTP and POP3 in exchange 2000 environment. Do u have any comments? Regards Aboo Arif