Linux.by

Код: Выделить всё

$ telnet 195.209.34.118 25
Trying 195.209.34.118...
telnet: Unable to connect to remote host: Connection refused
$ telnet 195.209.34.118 2525
Trying 195.209.34.118...
telnet: Unable to connect to remote host: Connection refused
$ host tut.by
tut.by              	A	195.209.34.118
$ host mail.tut.by
mail.tut.by         	A	195.209.41.194
$ telnet 195.209.41.194 25
Trying 195.209.41.194...
Connected to 195.209.41.194.
Escape character is '^]'.
220 TUT.BY ESMTP Server at speedy.tutby.com is ready to rock!
quit
221 tut.by TUT.BY SMTP Server at speedy.tutby.com is closing connection
Connection closed by foreign host.
$

Код: Выделить всё

 Route all outgoing mail to your network provider.

If your machine is disconnected most of the time, there isn't a lot of opportunity for Postfix to deliver mail to hard-to-reach corners of the Internet. It's better to give the mail to a machine that is connected all the time. In the example below, the [] prevents Postfix from trying to look up DNS MX records.

/etc/postfix/main.cf:
    relayhost = [smtprelay.someprovider.com]

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Postfix on hosts without a real hostname

This section is for hosts that don't have an Internet hostname. Typically these are systems that get a dynamic IP address via DHCP or via dialup. Postfix will let you send and receive mail just fine between accounts on a machine with a fantasy name. However, you cannot use a fantasy hostname in your email address when sending mail into the Internet, because no-one would be able to reply to your mail. In fact, more and more sites refuse mail from non-existent domain names.

The perfect solution would be for Postfix to do a mapping from local fantasy email addresses to valid Internet addresses when mail leaves the machine (similar to Sendmail's generics table). This is planned for the near future.

In the mean time, the solution with Postfix is to use valid Internet addresses where possible, and to let Postfix map valid Internet addresses to local fantasy addresses. With this, you can send mail to the Internet and to local fantasy addresses, including mail to local fantasy addresses that don't have a valid Internet address of their own.
 The following example presents additional configuration. You need to combine this with basic configuration information as discussed the first half of this document.

 1 /etc/postfix/main.cf:
 2     myhostname = hostname.localdomain
 3     mydomain = localdomain
 4 
 5     canonical_maps = hash:/etc/postfix/canonical
 6 
 7     virtual_alias_maps = hash:/etc/postfix/virtual
 8 
 9 /etc/postfix/canonical:
10     your-login-name    your-account@your-isp.com
11 
12 /etc/postfix/virtual:
13     your-account@your-isp.com       your-login-name

Translation:

* Lines 2-3: Substitute your fantasy hostname here. Do not use a domain name that is already in use by real organizations on the Internet. See RFC 2606 for examples of domain names that are guaranteed not to be owned by anyone.
* Lines 5, 9, 10: This provides the mapping from "your-login-name@hostname.localdomain" to "your-account@your-isp.com". This part is required.
* Lines 7, 12, 13: Deliver mail for "your-account@your-isp.com" locally, instead of sending it to the ISP. This part is not required but is convenient. 

Код: Выделить всё

telnet 195.209.41.194 2525