#!/bin/sh recipients='info@odesk.by' subject='vh36 test sendmail' from='redmine@redmine.odesk.by' /usr/sbin/sendmail "$recipients" <<EOF subject:$subject from:$from vh36 test sendmail EOF
Category: sendmail
CentOS: Securing Sendmail with TLS
One of the most common uses of network systems is for e-mail-basedcommunications. As such, a great deal of attention has been given to securing e-mail systems. Howe
ver, most of this focus has been in two areas – security at the message level, using PGP or S/MIME, and confidentiality in the authentication process for mail retrieval, i.e., using APOP or SSL-based IMAP. This still leaves mail server-to-server traversal vulnerable to several attacks.
The introduction of basic cryptography into a mail server-to-server session alleviates most of these risks. Mail transport agents(MTA) and software such as Sendmail or Postfix can be augmented to handle their communications over transaction layer security(TLS) channels. This provides for a number of services, including confidentiality, integrity protection and strong authentication.
This article will introduce the features and use of SMTP over TLS as defined in RFC 2487, as well as illustrate their setup in the Sendmail package. We will cover cryptography basics, though not delve into the mathematics of cryptosystems and simple mail transfer protocol (SMTP) and extended simple mail transfer protocol(ESMTP) basics.
Some Basics of Cryptography
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Linux Network Admin : SENDMAIL: sendmail’s options
Опции sendmail
Пакет sendmail имеет ряд параметров, которые позволяют Вам настраивать выполнение ряда задач. Я рассмотрю лишь основные,полный перечень огромен. Чтобы конфигурировать любые из этих параметров, Вы можете определять их в
файле конфигурации m4, что является предпочтительным методом, или вставлять их непосредственно в файл sendmail.cf. Например, если нужно, чтобы sendmail запускал новый процесс для каждого сообщения почты, нужно добавить строку к файлу конфигурации m4:
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Where to put the check_* rulesets in sendmail
check_* in .mc
Usually the
1 | sendmail.cf |
file should be built from a
1 | .mc |
file with help of the m4 macro language processor . Use the supplied HACKs or put the rules(e.g.,check_mail or check_rcpt ) as given into the .mc file. Make sure that you have the CODE>LOCAL_CONFIG and
1 | LOCAL_RULESETS |
in front of the respective sections, otherwise there will be some problems!
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