User manual

Using email on the Qube 3
Cobalt Qube 3 User Manual 41
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 Qube 3 accepts email if the recipient has a user account or an alias email
account, or if the sending host (your client computer) 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. A network is a range of
IP addresses; a network can be as small as one IP address, but that is not very
practical.
If you have users who access your server through the Internet, ask your ISP
which networks are used by their remote access (dial-up) equipment. If the ISP
says the network 209.43.21.5/24 and 209.48.66.5/16, add “209.43.21.0” and
“209.48.0.0” to the “Relay email from these hosts/domains” field of the Email
Parameters menu. If your ISP gives you a list of 30 networks used by 30 points-
of-presence (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 Qube 3.
!
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 Cobalt server; this relayed mail is often 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.
✍-
Note: By default, the domain name for the Qube 3 is allowed to
relay email.
If you do not want to allow email to be sent through the Qube 3,
enter the domain name of the Qube 3 in the “Block Email From
Hosts/Domains” field. You will be able to download email but not
be able to send outgoing email messages through Qube 3.
For more information, see “Configuring the email settings” on
page 131.