User manual

Chapter 3: RaQ 4 Server Management
56 Cobalt RaQ 4 User Manual
Email relaying
Simple Mail Transfer Protocol (SMTP) service is different from Post Office
Protocol (POP), telnet and file transfer protocol (FTP) services in that SMTP
does not try to authenticate a user when an SMTP connection is made.
Every email server on the Internet has to be able to deliver email to you, so the
email servers must be able to connect freely to send the email. The RaQ 4 accepts
email for processing if the recipient has a user account or an alias email account,
or if the sending host (your client PC) is trusted to relay outgoing email messages
to another domain. These trusts are defined by host or domain names, as well as
by IP addresses and networks.
If you have users who access your server through the Internet, ask your Internet
service provider (ISP) which networks are used by their remote access (dial-up)
equipment.
For example, if the ISP says the network 192.168.10.5 through 192.168.10.24,
then enter “192.168.10” in the “Relay email from these hosts/domains” field of
the Email Parameters table. If your ISP gives you a list of 30 networks used by 30
points-of-presence (POPs) (which are regional ISP offices) across the country
and your clients can dial in from any of them, then you must trust all 30 networks
or these users cannot send email through your RaQ 4.
!
Caution: Some users advise you to open relay to all com, edu, net
and other top-level domain addresses. However, doing so allows
hosts belonging to com, edu, net and others to relay email through
your server; this relayed mail is known as spam mail.
Spam mail can appear as though it originated from your server and
as a result, others may blacklist your server as a known spam site. If
your server is blacklisted, many mail servers will not relay your
email and your customers will not receive a large amount of their
email messages.