Hi All I'm new in exchange and administration, I try to connect to exchange server 2003 to pop specific usermails, but bellow exception occured: "ERROR 10061 : No connection could be made because the target machine actively refused it." i can't telnet to server on port 110, I can send email from gmail andother mail serversto my server but when i want to telnet to the server on port 25 it's not possible. my situation is as below: I have a NAT server that routs messages to my exchange server machin. NAT server is connected to internet. exchange server connected to internet via NAT. NAT server ip address is 82.99.225.166, I can connect to exchange server locally or in windows groupvia pop connector or telnet and works fine. I have some search around this problem, I think is related to Fire Wall setting, but I don't know what is a problem, wich policies are important in NAT, ... I use some IP Sniffer to find the problem and I found that in telnet packets are received on NAT server but they didn't receive on Exchange Server Machin. but when using gmail to send a mail packets on port 25 rich to both of NAT and exchange. Any Help, I'm so confused!

First, you are statingthat you think it's your firewall? What type of firewall do you have? and have you opened the correct ports. I would assume that you set the IP to dynamic, you need to change it to a Static IP if it is not already set. Once it is set, you need to direct the service to that IP address (for instance, 192.168.2.10). Pop3 on port 110 is the older of the two popular protocols used to retrieve eMail from remote mail servers. (The newer protocol, imap, the Internet message access protocol, uses port 143.) end eMail to remote eMail servers using the SMTP protocol on port 25. If you want to telnet, you need to telnet using port 23. I wouldn't recommend giving your public ip address either... Also, you need to make sure that you have pop3 enabled on exchange server.