There are three different types of Out Mail type: SMTP Relay, SMTP Direct and VPOP3 File Transfer
The details below are for SMTP Direct, click here for SMTP Relay or here for VPOP3 File Transfer settings.
The Only send messages waiting at start of connection option tells VPOP3 not to send any messages which arrive in the OutQueue once the outgoing connection has started.
The Send smaller messages first option tells VPOP3 to sort the outgoing messages into size order and send the smaller messages first, followed by the larger messages.
Sending outgoing mail using Direct SMTP means that the messages do not go through your ISP's mail server. In some cases (especially when you have a fast Internet connection) this may be quicker than going through your ISP's mail server. If you have a slow Internet connection, it is usually quicker to use the Via SMTP Relay method.
See here for technical information on how the Direct SMTP method works.
In the DNS Servers box you must type the IP address of your ISP's DNS server(s). Your ISP will normally be able to provide you with this information. If they are unwilling to do so, you can normally find the information by using the WINIPCFG (on Windows 95/98/ME) or IPCONFIG (on Windows NT/ 2000/XP/2003) programs. You can specify one or more DNS servers here - separate them with commas.
The DNS Overrides let you specify that email to certain domains should be sent through a different mail server from the one defined in the DNS system. This can be useful if certain email domains block mail directly from your VPOP3 server for some reason, but will allow it if it passes through your ISP's relay server.
The MX Routing Global Settings apply to all SMTP Direct settings, they are not different for each Out Mail method.
MX Routing Retry - If VPOP3 is unable to send a message the first time it tries it will often store the message to try again later. This setting tells VPOP3 how long it should wait before trying again. Note that this tells VPOP3 when to put the failed message back into the OutQueue. If VPOP3 is connecting via a dial-up connection, it will not necessarily dial up after this time, it will still wait until the next scheduled time.
DNS Cache Size - For SMTP Direct sending, VPOP3 needs to look up the IP addresses of the recipient's email server for each message. It finds this address by using the DNS Server specified on this page. VPOP3 can remember a certain number of IP addresses so that it doesn't need to look up the address again if it finds another message to the same person (or a different person at the same email domain). Each entry in the DNS cache uses a bit more memory (approx 60 bytes per entry), so don't set it to a massive size unnecessarily.
DNS Cache Expiry - This tells VPOP3 how long to keep entries in the DNS entry cache. If it is set too long, VPOP3 might remember out of date entries, and if it is too short, the cache won't be utilised as well as it could be.
MX Sending Threads VPOP3 will process multiple messages at once when sending mail using direct SMTP Direct. This setting tells VPOP3 how many messages to process at once. If you set the value too high, then it will actually slow down. A value of 5 - 10 is best for a modem dial up connection, 10 - 20 is best for ISDN and faster connections can use larger values.
Don't Send Delivery Warnings If VPOP3 receives an error which it can interpret as an intermittent failure (eg the remote mail server is down), it will try to send the message again later. If it hasn't sent the message within 4 hours of first trying, it will normally issue a warning message to the sender or administrator An Administrator is a VPOP3 user who is allowed to change VPOP3 settings, add/remove users, view queued messages etc.. If it still hasn't sent the message after 3 days, it will fail the message permanently and send an error message to the sender or administrator. If you enable the Don't Send Warnings option, VPOP3 won't send the 4 hour warning, it will just send a message when it has given up trying to send the message.
Only Send one Warning per target domain per Day If this option is set, VPOP3 will only send one warning message (see above for the difference between warnings and errors) for each destination email domain per day. This can be useful if VPOP3 is mainly used as a listserver. If VPOP3 is used as a normal mail server, then this will mean that the message sender may not get a warning about a message if it couldn't be sent immediately, so it is best to leave this option turned off in most cases.
Setting
Up a Connection Schedule
