we have exchange 2000 standard server published through ISA server. Now we have the new internet connection through another ISP. they provided us with the Cisco 1710 router and a single Public IP. They configured it as a NAT to provide internet access to cleints. We now want to direct our exchange 2000 server through the new ISP connection and leave the old ISP connection for clients internet access through ISA, so that we can define access policies based no usernames. i have some questions regarding this. - what ports should i open on the Cisco 1710 router to allow exchange 2000 server to recieve and send internet e-mails.what is the recommended router configuration for this.(configuration details of 1710 is desired,if any). -Should we change MX record to the new public IP. -how safe is it to configure exchange server through Cisco 1710 as compared to ISA server publishing. what configuration is required on the cisco router to provide maximum security. i hope the experts here will guide me for the best design and configuration! Thanks in advance.