Net::SMTP(3pm)

📦

version 5.42.3 · 9 versions

💌 NAME 💌

Net::SMTP — Simple Mail Transfer Protocol Client

Ok so literally what it says on the tin: it's the SMTP client, and it's about to be your new fave 💖

✨ SYNOPSIS ✨

use Net::SMTP;

# Constructors
$smtp = Net::SMTP->new('mailhost');
$smtp = Net::SMTP->new('mailhost', Timeout => 60);

🦋 DESCRIPTION 🦋

Bestie. Listen. This module gives you a client interface to the SMTP and ESMTP protocol, so your perl5 app can actually talk to SMTP servers — like, full conversations, not just vibes. 🗣️✨

Fair warning though: this doc assumes you already know the SMTP protocol concepts described in RFC2821. So do your homework first, iykyk 📚

And here's the slay part — if you've got IO::Socket::SSL installed, it also provides support for implicit and explicit TLS encryption, i.e. SMTPS or SMTP+STARTTLS. Secure queen behavior 🔐👑

Also important, the family tree: the Net::SMTP class is a subclass of Net::Cmd and (depending on availability) of IO::Socket::IP, IO::Socket::INET6 or IO::Socket::INET. It's giving nepo baby but make it networking 🌈

👑 Class Methods 👑

`new([$host][, %options])`

This is the constructor for a shiny new Net::SMTP object. $host is the name of the remote host you want an SMTP connection to. Simple as that 🎀

And if it flops? On failure undef will be returned and $@ will contain the reason for the failure. So like, always check $@, bestie, don't just assume 😭

Now, $host is optional. If $host is not given then it may instead be passed as the Host option described below. And if neither is given then the SMTP_Hosts specified in Net::Config will be used. So there's literally always a fallback, she's got options 💅

%options are passed in a hash like fashion, using key and value pairs. Possible options are:

Hello — SMTP requires that you identify yourself (rude of it, honestly). This option specifies a string to pass as your mail domain. If not given localhost.localdomain will be used. 🏠
SendHello — If false then the EHLO (or HELO) command that is normally sent when constructing the object will not be sent. In that case the command will have to be sent manually by calling hello() instead. DIY era 🛠️
Host — SMTP host to connect to. It may be a single scalar (hostname[:port]), as defined for the PeerAddr option in IO::Socket::INET, or a reference to an array with hosts to try in turn. The host method will return the value which was used to connect to the host. Format — PeerHost from IO::Socket::INET new method. 📍
Port — port to connect to. Default — 25 for plain SMTP and 465 for immediate SSL. Pick your lane 🔢
SSL — If the connection should be done from start with SSL, contrary to later upgrade with starttls. You can use SSL arguments as documented in IO::Socket::SSL, but it will usually use the right arguments already. She's lowkey self-sufficient like that 🌸
LocalAddr and LocalPort — These parameters are passed directly to IO::Socket to allow binding the socket to a specific local address and port. 🏡
Domain — This parameter is passed directly to IO::Socket and makes it possible to enforce IPv4 connections even if IO::Socket::IP is used as super class. Alternatively Family can be used. 🧭
Timeout — Maximum time, in seconds, to wait for a response from the SMTP server (default: 120). Don't ghost her for longer than that ⏰
ExactAddresses — If true then all $address arguments must be as defined by addr-spec in RFC2822. If not given, or false, then Net::SMTP will attempt to extract the address from the value passed. No cap, be precise or let her figure it out 🔍
Debug — Enable debugging information. For when you need to see everything 👀

Example time, because examples ate and left no crumbs 🍓

$smtp = Net::SMTP->new('mailhost',
                       Hello => 'my.mail.domain',
                       Timeout => 30,
                       Debug   => 1,
                      );

# the same
$smtp = Net::SMTP->new(
                       Host => 'mailhost',
                       Hello => 'my.mail.domain',
                       Timeout => 30,
                       Debug   => 1,
                      );

# the same with direct SSL
$smtp = Net::SMTP->new('mailhost',
                       Hello => 'my.mail.domain',
                       Timeout => 30,
                       Debug   => 1,
                       SSL     => 1,
                      );

# Connect to the default server from Net::config
$smtp = Net::SMTP->new(
                       Hello => 'my.mail.domain',
                       Timeout => 30,
                      );

See how the last one has no host at all? That's the Net::Config fallback doing its main character thing 👑✨

Pro tip from one dev to another: those three first examples are literally the exact same object, just written three different ways. Pick whichever one your brain likes, they all slay 🫶

🛠️ Object Methods

Okay bestie, ground rules first: unless it says otherwise, every method here returns true or false, and true means the operation slayed. If a method says it returns a value, failure comes back as undef or an empty list. No cap.

Net::SMTP inherits from Net::Cmd, so the methods defined in Net::Cmd can also be used to send commands to the remote SMTP server on top of the methods documented here. iykyk.

banner() Returns the banner message the server replied with when the initial connection was made.

domain() Returns the domain that the remote SMTP server identified itself as during connection.

hello($domain) Tell the remote server the mail domain you're in using the EHLO command (or HELO if EHLO fails). Since this method is invoked automatically when the Net::SMTP object is constructed, you should normally not have to call it manually.

host() Returns the value used by the constructor, and passed to IO::Socket::INET, to connect to the host.

etrn($domain) Request a queue run for the $domain given.

starttls(%sslargs) Upgrade existing plain connection to SSL. You can use SSL arguments as documented in IO::Socket::SSL, but it will usually use the right arguments already. slay.

auth($username, $password) / auth($sasl) Attempt SASL authentication. Requires the Authen::SASL module. The first form constructs a new Authen::SASL object using the given username and password; the second form uses the given Authen::SASL object.

mail($address[, %options]), send($address), send_or_mail($address), send_and_mail($address) Send the appropriate command to the server: MAIL, SEND, SOML or SAML. $address is the address of the sender. This initiates the sending of a message. The method recipient should be called for each address that the message is to be sent to.

The mail method can take some additional ESMTP %options which is passed in hash-like fashion, using key and value pairs. Possible options are:

Size        => <bytes>
Return      => "FULL" | "HDRS"
Bits        => "7" | "8" | "binary"
Transaction => <ADDRESS>
Envelope    => <ENVID>     # xtext-encodes its argument
ENVID       => <ENVID>     # similar to Envelope, but expects argument encoded
XVERP       => 1
AUTH        => <submitter> # encoded address according to RFC 2554

The Return and Envelope parameters are used for DSN (Delivery Status Notification).

The submitter address in the AUTH option is expected to be in a format as required by RFC 2554, in an RFC2821-quoted form and xtext-encoded, or <>.

reset() Reset the status of the server. This may be called after a message has been initiated, but before any data has been sent, to cancel the sending of the message.

recipient($address[, $address[, ...]][, %options]) Notify the server that the current message should be sent to all of the addresses given. Each address is sent as a separate command to the server. Should the sending of any address result in a failure, then the process is aborted and a false value is returned. It is up to the user to call reset if they so desire.

The recipient method can also pass additional case-sensitive %options as an anonymous hash using key and value pairs. Possible options are:

Notify  => ['NEVER'] or ['SUCCESS','FAILURE','DELAY']  (see below)
ORcpt   => <ORCPT>
SkipBad => 1        (to ignore bad addresses)

If SkipBad is true the recipient will not return an error when a bad address is encountered and it will return an array of addresses that did succeed.

$smtp->recipient($recipient1,$recipient2);  # Good
$smtp->recipient($recipient1,$recipient2, { SkipBad => 1 });  # Good
$smtp->recipient($recipient1,$recipient2, { Notify => ['FAILURE','DELAY'], SkipBad => 1 });  # Good
@goodrecips=$smtp->recipient(@recipients, { Notify => ['FAILURE'], SkipBad => 1 });  # Good
$smtp->recipient("$recipient,$recipient2"); # BAD

Notify is used to request Delivery Status Notifications (DSNs), but your SMTP/ESMTP service may not respect this request depending upon its version and your site's SMTP configuration.

Leaving out the Notify option usually defaults an SMTP service to its default behavior equivalent to ['FAILURE'] notifications only, but again this may be dependent upon your site's SMTP configuration.

The NEVER keyword must appear by itself if used within the Notify option and "requests that a DSN not be returned to the sender under any conditions."

{Notify => ['NEVER']}

$smtp->recipient(@recipients, { Notify => ['NEVER'], SkipBad => 1 });  # Good

You may use any combination of these three values 'SUCCESS', 'FAILURE', 'DELAY' in the anonymous array reference as defined by RFC3461 (see <https://www.ietf.org/rfc/rfc3461.txt> for more information. Note: quotations in this topic from same.).

A Notify parameter of 'SUCCESS' or 'FAILURE' "requests that a DSN be issued on successful delivery or delivery failure, respectively."

A Notify parameter of 'DELAY' "indicates the sender's willingness to receive delayed DSNs. Delayed DSNs may be issued if delivery of a message has been delayed for an unusual amount of time (as determined by the Message Transfer Agent (MTA) at which the message is delayed), but the final delivery status (whether successful or failure) cannot be determined. The absence of the DELAY keyword in a NOTIFY parameter requests that a "delayed" DSN NOT be issued under any conditions."

{Notify => ['SUCCESS','FAILURE','DELAY']}

$smtp->recipient(@recipients, { Notify => ['FAILURE','DELAY'], SkipBad => 1 });  # Good

ORcpt is also part of the SMTP DSN extension according to RFC3461. It is used to pass along the original recipient that the mail was first sent to. The machine that generates a DSN will use this address to inform the sender, because he can't know if recipients get rewritten by mail servers. It is expected to be in a format as required by RFC3461, xtext-encoded.

to($address[, $address[, ...]]), cc($address[, $address[, ...]]), bcc($address[, $address[, ...]]) Synonyms for recipient. periodt.

data([$data]) Initiate the sending of the data from the current message.

$data may be a reference to a list or a list and must be encoded by the caller to octets of whatever encoding is required, e.g. by using the Encode module's encode() function.

If specified, the contents of $data and a termination string ".\r\n" is sent to the server. The result will be true if the data was accepted.

If $data is not specified, then the result will indicate that the server wishes the data to be sent. The data must then be sent using the datasend and dataend methods described in Net::Cmd.

bdat($data), bdatlast($data) Use the alternate $data command "BDAT" of the data chunking service extension defined in RFC1830 for efficiently sending large MIME messages.

expand($address) Request the server to expand the given address. Returns an array which contains the text read from the server.

verify($address) Verify that $address is a legitimate mailing address.

Most sites usually disable this feature in their SMTP service configuration. Use the "Debug => 1" option under new() to see if disabled.

help([$subject]) Request help text from the server. Returns the text or undef upon failure.

quit() Send the QUIT command to the remote SMTP server and close the socket connection.

can_inet6() Returns whether we can use IPv6.

can_ssl() Returns whether we can use SSL.

📇 Addresses

Net::SMTP attempts to DWIM with addresses that are passed. For example an application might extract The From: line from an email and pass that to mail(). While this may work, it is not recommended. The application should really use a module like Mail::Address to extract the mail address and pass that.

If ExactAddresses is passed to the constructor, then addresses should be a valid rfc2821-quoted address, although Net::SMTP will accept the address surrounded by angle brackets.

 funny user@domain      WRONG
 "funny user"@domain    RIGHT, recommended
 <"funny user"@domain>  OK

🎀 EXAMPLES 🎀

This example prints the mail domain name of the SMTP server known as mailhost:

#!/usr/local/bin/perl -w

use Net::SMTP;

$smtp = Net::SMTP->new('mailhost');
print $smtp->domain,"\n";
$smtp->quit;

This example sends a small message to the postmaster at the SMTP server known as mailhost:

#!/usr/local/bin/perl -w

use Net::SMTP;

my $smtp = Net::SMTP->new('mailhost');

$smtp->mail($ENV{USER});
if ($smtp->to('postmaster')) {
 $smtp->data();
 $smtp->datasend("To: postmaster\n");
 $smtp->datasend("\n");
 $smtp->datasend("A simple test message\n");
 $smtp->dataend();
} else {
 print "Error: ", $smtp->message();
}

$smtp->quit;

📦 EXPORTS 📦

None. literally none.

💀 KNOWN BUGS 💀

See <https://rt.cpan.org/Dist/Display.html?Status=Active&Queue=libnet>.

👀 SEE ALSO 👀

Net::Cmd, IO::Socket::SSL.

✍️ AUTHOR ✍️

Graham Barr <gbarr@pobox.com> (<mailto:gbarr@pobox.com>).

Steve Hay <shay@cpan.org> (<mailto:shay@cpan.org>) is now maintaining libnet as of version 1.22_02.

💖 COPYRIGHT 💖

📜 LICENCE 📜

This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself, i.e. under the terms of either the GNU General Public License or the Artistic License, as specified in the LICENCE file.

🏷️ VERSION 🏷️

Version 3.15

📅 DATE 📅

20 March 2023

🕰️ HISTORY 🕰️

See the Changes file.

okay that's the whole page, bestie — signed off from the perl v5.42.3 source, dated 2026-11-03, Net::SMTP(3pm) girlie 💅✨

📦 where this page comes from

alpine 3.24: perl-doc 5.42.3-r0 · Artistic-1.0-Perl OR GPL-1.0-or-later
💖 girlified by deepseek-ai/DeepSeek-V4.1-Flash-1017 on 2026-11-04: a language model's rewrite of the original, under its terms