I've a client which has Exchange 2010 installed. He is thinking to have POP3 connector to get all emails from his provider as opposed to native redirection of all MX records to this server. He feels safer that emails are never lost there when he occasionally reboot server or do some other stuff on it and theoretically POP3 connector gives him that.
I've told him that we can always do MX redirection to his server and then keep his provider emails MX server as 2nd one so when his server gets rebooted emails will go to 2nd server and we will get his emails with connectors for his safety.
To make it even harder currently this client uses dynamic IP which means we can't use anything else then connector but if he's convinced to Exchange as native solution he would buy out the static IP.
So what are benefits and downsides of having Exchange working in native mode? I can name a few myself.
- control over how emails are handled
- using pop3 connectors may not always work
- access to OWA is much greater probability to work with static IP then dynamic one
- spam / viruses have to be taken care of which means buying a software to do so (but you do get better control over what your email server accept and what they not as opposed to provider email system)
- have to pay attention to your IP to not get marked as spammer yourself (as for example spamming computer in your network may cause your all emails to be marked as spam later on)
- bigger costs due to need for static IP and additional software
- longer downtime can cause emails to be lost (short downtime's usually have no impact on email flow