Книга: Fedora™ Unleashed, 2008 edition
Rejecting Email from Specified Sites
Rejecting Email from Specified Sites
You read earlier in this chapter that you must be careful with mail relaying to avoid becoming a spam magnet. But what do you do if you are having problems with a certain site sending you spam? You can use the /etc/mail/access file to automatically reject mail from certain sites.
You can use several rules in the access file. Table 21.1 lists these rules.
TABLE 21.1 The Various Possible Options for Access Rules
| Option | Action |
|---|---|
OK |
Accepts mail from this site, overriding any rules that would reject mail from this site. |
RELAY |
Allows this domain to relay through the server. |
REJECT |
Rejects mail from this site and sends a canned error message. |
DISCARD |
Simply discards any message received from the site. |
ERROR: "n message" |
Sends an error message back to the originating server, where n is an RFC 821-compliant error code number. The message itself can be anything you want. |
The following is an example of three rules used to control access to a Sendmail account. The first rejects messages from spam.com. The second rejects messages from lamer.com and displays an error message to that site. The third allows mail from the specific host user5.lamer.com, even though there is a rule that rejects mail from the site lamer.com.
NOTE
For a more personal example of why you would bother to do this, I find that I get a lot of spam from the Hotmail domain, so I would just as soon reject it all. However, my wife uses a Hotmail account for her mail. If I did not allow her mail through, that would be a problem for me.
spam.com REJECT
lamer.com ERROR: "550 Mail from spammers is not accepted at this site."
user5.lamer.com OK
Open the /etc/access file, enter the rules of your choice, and then restart Sendmail so that your changes to the access file take effect. That can be done with
# service sendmail restart
or any of the other ways discussed in Chapter 11, "Automating Tasks."
Оглавление книги
- Инструкция INSERT INTO ... FROM ... UNION ...
- Prerequisites
- User specified chains
- Setting up user specified chains in the filter table
- Creating CDs from the Command Line
- Chapter 2. Four Puzzles From Cyberspace
- Installing from CD or DVD
- Starting X from the Console by Using startx
- Use Essential Commands from the
- Logging In and Out from a Remote Computer
- Choosing an Email Client
- Creating DVDs from the Command Line