Package smtpd

import "bitbucket.org/chrj/smtpd"

Overview
Index
Examples
Subdirectories

Overview

Package smtpd implements an SMTP server with support for STARTTLS, authentication (PLAIN/LOGIN), XCLIENT and optional restrictions on the different stages of the SMTP session.

Index

type Envelope
func (env *Envelope) AddReceivedLine(peer Peer)
type Error
func (e Error) Error() string
type Peer
type Protocol
type Server
func (srv *Server) ListenAndServe(addr string) error
func (srv *Server) Serve(l net.Listener) error

Examples

(Expand All)

Server

Package files

address.go envelope.go protocol.go smtpd.go wrap.go

type Envelope

Envelope holds a message

type Envelope struct {
    Sender     string
    Recipients []string
    Data       []byte
}

func (*Envelope) AddReceivedLine

func (env *Envelope) AddReceivedLine(peer Peer)

AddReceivedLine prepends a Received header to the Data

type Error

Error represents an Error reported in the SMTP session.

type Error struct {
    Code    int    // The integer error code
    Message string // The error message
}

func (Error) Error

func (e Error) Error() string

Error returns a string representation of the SMTP error

type Peer

Peer represents the client connecting to the server

type Peer struct {
    HeloName   string               // Server name used in HELO/EHLO command
    Username   string               // Username from authentication, if authenticated
    Password   string               // Password from authentication, if authenticated
    Protocol   Protocol             // Protocol used, SMTP or ESMTP
    ServerName string               // A copy of Server.Hostname
    Addr       net.Addr             // Network address
    TLS        *tls.ConnectionState // TLS Connection details, if on TLS
}

type Protocol

Protocol represents the protocol used in the SMTP session

type Protocol string

const (
    SMTP  Protocol = "SMTP"
    ESMTP          = "ESMTP"
)

type Server

Server defines the parameters for running the SMTP server

type Server struct {
    Hostname       string // Server hostname. (default: "localhost.localdomain")
    WelcomeMessage string // Initial server banner. (default: "<hostname> ESMTP ready.")

    ReadTimeout  time.Duration // Socket timeout for read operations. (default: 60s)
    WriteTimeout time.Duration // Socket timeout for write operations. (default: 60s)
    DataTimeout  time.Duration // Socket timeout for DATA command (default: 5m)

    MaxConnections int // Max concurrent connections, use -1 to disable. (default: 100)
    MaxMessageSize int // Max message size in bytes. (default: 10240000)
    MaxRecipients  int // Max RCPT TO calls for each envelope. (default: 100)

    // New e-mails are handed off to this function.
    // Can be left empty for a NOOP server.
    // If an error is returned, it will be reported in the SMTP session.
    Handler func(peer Peer, env Envelope) error

    // Enable various checks during the SMTP session.
    // Can be left empty for no restrictions.
    // If an error is returned, it will be reported in the SMTP session.
    // Use the Error struct for access to error codes.
    ConnectionChecker func(peer Peer) error              // Called upon new connection.
    HeloChecker       func(peer Peer, name string) error // Called after HELO/EHLO.
    SenderChecker     func(peer Peer, addr string) error // Called after MAIL FROM.
    RecipientChecker  func(peer Peer, addr string) error // Called after each RCPT TO.

    // Enable PLAIN/LOGIN authentication, only available after STARTTLS.
    // Can be left empty for no authentication support.
    Authenticator func(peer Peer, username, password string) error

    EnableXCLIENT       bool // Enable XCLIENT support (default: false)
    EnableProxyProtocol bool // Enable proxy protocol support (default: false)

    TLSConfig *tls.Config // Enable STARTTLS support.
    ForceTLS  bool        // Force STARTTLS usage.

    ProtocolLogger *log.Logger
}

Example

Code:

var server *smtpd.Server

// No-op server. Accepts and discards
server = &smtpd.Server{}
server.ListenAndServe("127.0.0.1:10025")

// Relay server. Accepts only from single IP address and forwards using the Gmail smtp
server = &smtpd.Server{

    HeloChecker: func(peer smtpd.Peer, name string) error {
        if !strings.HasPrefix(peer.Addr.String(), "42.42.42.42:") {
            return errors.New("Denied")
        }
        return nil
    },

    Handler: func(peer smtpd.Peer, env smtpd.Envelope) error {

        return smtp.SendMail(
            "smtp.gmail.com:587",
            smtp.PlainAuth(
                "",
                "username@gmail.com",
                "password",
                "smtp.gmail.com",
            ),
            env.Sender,
            env.Recipients,
            env.Data,
        )

    },
}

server.ListenAndServe("127.0.0.1:10025")

func (*Server) ListenAndServe

func (srv *Server) ListenAndServe(addr string) error

ListenAndServe starts the SMTP server and listens on the address provided

func (*Server) Serve

func (srv *Server) Serve(l net.Listener) error

Serve starts the SMTP server and listens on the Listener provided

Subdirectories

Name	Synopsis

examples
examples/dkim-proxy	Command dkim-proxy implements a simple SMTP proxy that DKIM signs incoming e-mail and relays to another SMTP server for delivery

bitbucket.org/chrj/smtpd

Go smtpd

Moved to Github