Free via smtp software for linux

libsmtp allows programs to send mail directly through SMTP (no sendmail needed). lib smtp is designed to be simple and memory efficient, and has slightly untested support for MIME multipart body parts.

Socks via HTTP provides a socks tunnel via HTTP.

Socks via HTTP is a program converting SOCKS requests into HTTP requests and tunnelling them through HTTP proxies if needed.

The SOCKS protocol allows programs to traverse firewalls on any port number and is used by many popular programs, like Napster, MSN Messenger, CRT(telnet client) and many others.

Many companies restrict firewall traversals only to HTTP requests, disabling SOCKS proxy.

Socks via HTTP provides a miniature SOCKS server for the SOCKS client, performing its connection through an HTTP proxy to a remote server, which establishes the real connection.

Socks via HTTP is 100% Java, and can run on any OS. It is entirely written in Java.

libESMTP is an SMTP client which manages posting (or submission of) electronic mail via a preconfigured Mail Transport Agent (MTA).
libESMTP library may be used as part of a Mail User Agent (MUA) or other program that must be able to post electronic mail but where mail functionality is not that programs primary purpose.
The availability of a reliable lightweight thread-safe SMTP client eases the task of coding for software authors thus improving the quality of the resulting code.
Main features:
- libESMTP supports many SMTP extensions, notably PIPELINING (RFC 2920), DSN (RFC 1891) and SASL authentication (RFC 2554). SMTP AUTH is implemented using a SASL client library integrated into libESMTP. Supported SASL mechanisms include CRAM-MD5 and NTLM.
- libESMTP is also efficient. Because it buffers all network traffic, when used in conjunction with a pipelining SMTP server libESMTP significantly increases network performance, especially on slow connections and those with high latency. Even without a pipelining server libESMTP offers significantly better performance than would be expected with a simple client.
- libESMTP is not designed to be used as part of a program that implements a Mail Transport Agent. This is not because the code is unsuitable for use in an MTA, in fact the protocol engine is significantly better than those in many MTAs. Rather, by eliminating the need for MX lookup and next-hop determination, the design of libESMTP is simplified; thus goals are made achievable. Besides, such features are undesirable in a program that is not an MTA, particularly if the client is behind a firewall which blocks access to port 25 on the Internet.
Enhancements:
- This release applies bugfixes and plugs some memory leaks.
- It also attends to a few autoconf-related issues.

smtpauth is a authenticating proxy for servers without SMTP AUTH.

Use smtpauth and stunnel programs to add SMTP AUTH (PLAIN, LOGIN) support to any SMTP server. Clients can authenticate over SSL port 465 or cleartext port 587, and authentication is fully logged via syslog.

Works with JBMail, Pegasus Mail, Mozilla Thunderbird, MS Outlook...

This software is really an interim solution until our favourite MTA(s) support SSL/TLS and SMTP AUTH directly. For now I prefer using external programs to provide this functionality rather than patching MTA source. I designed this software to work with my Postfix server, but smtpauth also works with sendmail and just about any other SMTP server.

Installation:

1. Compile and install binary.

make
Copy smtpauth to /usr/sbin, owned by root, mode 755

2. Create special user smtpauth with its own group, no login allowed.

Note that smtpauth will immediately exit with an error if invoked as root.
It must be run from a low privilege account, for security.

3. [For SSL, port 465] Configure stunnel.conf. Change domain for your site.

setuid = smtpauth
setgid = smtpauth
debug = auth.notice
client = no

[smtps]
accept = 465
exec = /usr/sbin/smtpauth
execargs = smtpauth domain 127.0.0.1

4. Configure /etc/smtpauth.conf

This file should only be readable by the smtpauth user, since it stores plain
passwords. It consists of single lines containing usernames and passwords with
whitespace separating. Blank lines and comment lines starting # are ignored.

user1 pass1
user2 pass2

5. [For SSL, port 465] Start up stunnel

This will create a server running as smtpauth on port smtps/465. When SMTP clients
connect (SSL/TLS) the smtpauth program is launched and provides authentication
service through to 127.0.0.1:25, as a proxy. Your actual SMTP server will accept
mail because that connection is local. The mail headers will include X-SMTP-AUTH
indicating the username. Success and failures will be logged via syslog.

6. [For cleartext, port 587] Configure cleartext submission service in inetd

Since inetd (when started with -W) also supports wrapping, the smtpauth proxy
can be run straight out of here too. Note that this is somewhat risky, because
there will be no SSL/TLS encryption on the submission port (587).

Again, change domain for your site (e.g. mail.yoursite.tld)

submission stream tcp nowait smtpauth /usr/sbin/smtpauth smtpauth domain 127.0.0.1

SMTPGuard is a tool which controls the flow of email traversing an MTA (Mail Transfer Agent). It is designed to be used on an SMTP server for incoming mail, and currently supports postfix.
SMTPGuard was originally created to meet the needs of Internet Service Providers (ISPs). ISPs typically receive tremendous amounts of email from their local (user) network.
Within a wide variety of users, some are spammers, many unknowingly have virus infected PCs; each of these can send large quantities of mail through the ISPs SMTP (Simple Mail Transfer Protocol) servers.
This is especially a problem for ISPs who are connected to their users via high speed lines such as fiber or ADSL. SMTPGuard was developed to prevent SMTP servers from being overwhelmed by unexpected spikes in usage from specific (often malicious) users.
For a large ISP, their only problem isnt just with overloaded incoming SMTP servers. SPAM will also be queued on the outgoing server (perhaps the same server) for delivery to the Internet.
Because the mail is SPAM it will likely bounce, then double bounce putting extreme load on the outgoing server and its queue. smtpguard is designed to stop this type of extreme load by stopping floods of mail at the gate (incoming server).
SMTPGuard is point based. Each time a client connects to the SMTP server, SMTPGuard adds points according to the rules file. SMTPGuard uses information acquired during the SMTP session, adds points according to the rules file, and finally takes actions based on its settings. For example, the information below is used:
- Remote IP Address
- Character string provided by MAIL FROM command
- Character string provided by RCPT TO command
The following actions can be taken:
ok - white list
wait - delay processing
reject - reject messages
mail - send alert email to administrator
log - output message to log
delete - delete record in database
Enhancements:
- postfix/flexguard.c: remove word flexguard. use smtpguard instead. rename filename to postfix/smtpguard.c
- postfix/Makefile.am: rename flexguard -> smtpguard
- configure.in: 1.1.1
- rename FLEXGUARD_{CFLAGS,LIBS} -> SMTPGUARD_{CFLAGS,LIBS}
- smtpguard/Makefile.am,postfix/Makefile.am,test/Makefile.am: Ditto
- debian/postfix-smtpguard.files: added
- README.postfix: added

smtp-vilter is a high-performance content filter for sendmail, which detects email viruses and spam.

smtp-vilter can pass, discard, or simply mark an email based on the results of a content scan. It relies on third-party products for the actual content scan. It uses the milter API to communicate with sendmail, and backends to communicate with the actual scanning engines.

The backends can be chained to perform a series of checks on each message in one run.

Postfix SMTP Monitoring Solution is a set of three Perl CGI scripts used to monitor the SMTP queue, allowing the deletion of messages that for one reason or another become "stuck" in the queue.

I needed a web-based solution to monitor my Postfix SMTP relay, which enabled me to remove messages that become "stuck" in the queue. I wrote three simple Perl scripts, and used Sudo to give me the desired functionality.

I am uploading these scripts in case they are useful to others. Assuming you have Apache configured correctly on your Postfix server, it should be as easy as placing the three .cgi files into your webservers cgi-bin directory, and making the appropriate modifications to your /etc/sudoers file (see the README contained in the tarball).

Net::SMTP::TLS is an SMTP client supporting TLS and AUTH.

SYNOPSIS

use Net::SMTP::TLS;
my $mailer = new Net::SMTP::TLS(
your.mail.host,
Hello => some.host.name,
Port => 25, #redundant
User => emailguy,
Password=> s3cr3t);
$mailer->mail(emailguy@your.mail.host);
$mailer->to(someonecool@somewhere.else);
$mailer->data;
$mailer->datasend("Sent thru TLS!");
$mailer->dataend;
$mailer->quit;

Net::SMTP::TLS is a TLS and AUTH capable SMTP client which offers an interface that users will find familiar from Net::SMTP. Net::SMTP::TLS implements a subset of the methods provided by that module, but certainly not (yet) a complete mirror image of that API.

The methods supported by Net::SMTP::TLS are used in the above example. Though self explanatory for the most part, please see the perldoc for Net::SMTP if you are unclear.

The differences in the methods provided are as follows:
The mail method does not take the options list taken by Net::SMTP
The to method also does not take options, and is the only method available to set the recipient (unlike the many synonyms provided by Net::SMTP).
The constructor takes a limited number of Net::SMTPs parameters. The constructor for Net::SMTP::TLS takes the following (in addition to the hostname of the mail server, which must be the first parameter and is not explicitly named):

NoTLS - In the unlikely event that you need to use this class to perform non-TLS SMTP (you ought to be using Net::SMTP itself for that...), this will turn off TLS when supplied with a true value. This will most often cause an error related to authentication when used on a server that requires TLS
Hello - hostname used in the EHLO command
Port - port to connect to the SMTP service (defaults to 25)
Timeout - Timeout for inital socket connection (defaults to 5, passed directly to IO::Socket::INET)
User - username for SMTP AUTH
Password - password for SMTP AUTH