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NOTE: By default all Virtual Server's include the, so called "POP-before-SMTP"
anti-spam configuration. If you plan to use your Virtual Server as an SMTP relay for your
outgoing e-mail you must first authenticate your e-mail client IP address by
checking an e-mail account on the Virtual Server via POP or IMAP. For more details, see the
following.
How It Works
Every time someone successfully enters a correct username and password to your
Virtual Server POP or IMAP server (i.e. checks an e-mail account that is configured on your
Virtual Server), the server records the IP address of the remote client. The IP address and
a timestamp are stored in the ~/etc/relayers.db database file. The
database serves as a list of IP addresses that are allowed to perform an SMTP
relay. A simple rule set in the "check_rcpt" section of the ~/etc/sendmail.cf
file causes sendmail to refuse to relay e-mail from any IP address that
is not listed in the ~/etc/relayers.db database file. You will need to
add this Rule
Set if it is missing from your ~/etc/sendmail.cf file.
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vsmtprelay
Even though the POP and IMAP authentication will automatically cause an IP
address to be added to the ~/etc/relayers.db file, you may on occasion
want to manually add or clean the database yourself. To do this we have created
a utility program named vsmtprelay that allows you to add, delete,
expire, or list IP addresses in the ~/etc/relayers.db file.
% vsmtprelay
vsmtprelay 1.1.0 usage (optional items in []):
% vsmtprelay command [arg] [...]
where "command [arg] [...]" can be one of the following:
"add ip [ticks]" insert address with current timestamp (or ticks)
"delete ip [...]" remove specified address(es)
"expire [n]" expire all old (or older than n minutes) entries
"list [n]" list all old (or older than n minutes) entries
"dump" list every entry, including the future timestamped
IP addresses are expressed as ASCII "dotted quads", e.g. "10.11.12.13".
All timestamps are stored as ASCII strings representing a count of seconds
elapsed since 0 hours, 0 minutes, 0 seconds, January 1, 1970, Coordinated
Universal Time (the common UNIX epoch).
The ~/etc/relayers.db database is implemented as a "Berkeley DB
hash file" with IP addresses as keys and timestamps as the data (all as
ASCII strings). The vsmtprelay list output is intentionally produced in a
form that can be edited manually and rebuilt by makemap(8) if desired.
Although the ~/etc/relayers.db database does not use up a lot of disk
space on a Virtual Server, you may wish to automatically expire entries on a periodic basis
to keep the database small. This can be done using the Cron program scheduler.
For example, the following crontab entry would expire all of the day-old ~/etc/relayers.db
database entries every night at 3:15 AM.
15 3 * * * /usr/local/bin/vsmtprelay expire 1440
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NOTE: Some ISPs (Internet Service Providers) block transmissions on
port 25, the default SMTP port. On your Virtual Server, port 5190 can be used as an
alternative to port 25. Simply configure your e-mail client (as below) to use
port 5190 instead of 25, when using your Virtual Server as an SMTP relay.
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There are numerous e-mail clients (programs) available that support POP, or
both POP and IMAP, and SMTP. These include:
Configuring the typical e-mail client is generally a simple process.
Directions for configuring these three e-mail clients are detailed below.
Netscape Communicator
These directions apply to Communicator
4.5.
- From the "Edit" pull-down menu select the "Preferences" panel.
- Open the "Mail & Newsgroup" category (if not already open) by clicking
on the small triangle.
- Click on the "Mail Servers" sub-category.
- Select the "Add" button to the right of the "Incoming Mail Servers" section.
This will allow you to specify your server and the e-mail protocol you would
like to use (either POP or IMAP). The information requested is detailed below.
Server Name
This is typically your domain name, for example
"yourcompany.com".
Server Type
You will either need to select POP or IMAP. If you are
unsure which to select, we recommend you select POP.
User Name
This should be your e-mail user name, for example "bob"
for an e-mail address of bob@yourcompany.com
After you have provided the required information click "OK".
- In the "Outgoing Mail Server" section provide the following:
Outgoing mail (SMTP) server
This is typically your domain name, for
example "yourcompany.com".
Outgoing mail server user name
This should be your e-mail user
name, for example "bob" for an e-mail address of bob@yourcompany.com.
Microsoft Outlook
These directions apply to Outlook 2000.
- From the "Tools" pull-down menu select the "Accounts" panel.
- Select the "Mail" tab.
- Select "Add" and then "Mail" from the list provided.
- Follow the instructions provided by the wizard. Some tips are provided
below:
Incoming mail (POP3 or IMAP) server
This is typically your domain
name, for example "yourcompany.com".
Select either "POP3" or "IMAP"
If you are unsure which to select,
we recommend you select POP.
Outgoing mail (SMTP) server
This is typically your domain name, for
example "yourcompany.com".
Account Name
This should be your e-mail user name, for example
"bob" for an e-mail address of bob@yourcompany.com.
Password
This is be the password you associated with the Account
Name above.
Qualcomm Eudora
These
directions apply to Eudora Light 3.0.5
- From the "Tools" pull-down menu, select the "Options" panel.
- In the "Getting Started" section, provide the following:
POP account
This should be your e-mail user name, for example "bob"
for an e-mail address of bob@yourcompany.com.
Real name
This should be your own full name.
- In the "Personal Info" section, provide the following:
Return address
This should be your return e-mail address, which is
probably just your e-mail address.
- In the "Hosts" section, provide the following:
SMTP
This is either smtp.yourcompany.com, your-temp-domain.name, or
your ISP's SMTP server domain name.
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