SASLAUTHD(8) BSD System Manager's Manual SASLAUTHD(8)
NAME
saslauthd — sasl authentication server
SYNOPSIS
saslauthd -a authmech [-Tvdchlr] [-O option] [-m mux_path] [-n threads] [-s size] [-t timeout]
DESCRIPTION
saslauthd is a daemon process that handles plaintext authentication requests on behalf of the SASL library.
The server fulfills two roles: it isolates all code requiring superuser privileges into a single process, and it
can be used to provide proxy authentication services to clients that do not understand SASL based authentica‐
tion.
saslauthd should be started from the system boot scripts when going to multi-user mode. When running against a
protected authentication database (e.g. the shadow mechanism), it must be run as the superuser. Otherwise it is
recommended to run daemon unprivileged as saslauth:saslauth. You can do so by following these steps:
1. create directory /etc/systemd/system/saslauthd.service.d/
2. create file /etc/systemd/system/saslauthd.service.d/user.conf with content
[Service]
User=saslauth
Group=saslauth
3. Reload systemd service file: run “systemctl daemon-reload”
Options
Options named by lower-case letters configure the server itself. Upper-case options control the behavior of
specific authentication mechanisms; their applicability to a particular authentication mechanism is described in
the AUTHENTICATION MECHANISMS section.
-a authmech
Use authmech as the authentication mechanism. (See the AUTHENTICATION MECHANISMS section below.) This
parameter is mandatory.
-O option
A mechanism specific option (e.g. rimap hostname or config file path)
-H hostname
The remote host to be contacted by the rimap authentication mechanism. (Deprecated, use -O instead)
-m path
Use path as the pathname to the named socket to listen on for connection requests. This must be an abso‐
lute pathname, and MUST NOT include the trailing "/mux". Note that the default for this value is
"/var/state/saslauthd" (or what was specified at compile time) and that this directory must exist for
saslauthd to function.
-n threads
Use threads processes for responding to authentication queries. (default: 5) A value of zero will indi‐
cate that saslauthd should fork an individual process for each connection. This can solve leaks that
occur in some deployments.
-s size
Use size as the table size of the hash table (in kilobytes)
-t timeout
Use timeout as the expiration time of the authentication cache (in seconds)
-T Honour time-of-day login restrictions.
-v Print the version number and available authentication mechanisms on standard error, then exit.
-d Debugging mode.
Logging
saslauthd logs its activities via syslogd using the LOG_AUTH facility.
AUTHENTICATION MECHANISMS
saslauthd supports one or more "authentication mechanisms", dependent upon the facilities provided by the under‐
lying operating system. The mechanism is selected by the -a flag from the following list of choices:
dce (AIX)
Authenticate using the DCE authentication environment.
getpwent (All platforms)
Authenticate using the getpwent() library function. Typically this authenticates against the local
password file. See your system's getpwent(3) man page for details.
kerberos4 (All platforms)
Authenticate against the local Kerberos 4 realm. (See the NOTES section for caveats about this
driver.)
kerberos5 (All platforms)
Authenticate against the local Kerberos 5 realm.
pam (Linux, Solaris)
Authenticate using Pluggable Authentication Modules (PAM).
rimap (All platforms)
Forward authentication requests to a remote IMAP server. This driver connects to a remote IMAP
server, specified using the -O flag, and attempts to login (via an IMAP ‘LOGIN’ command) using the
credentials supplied to the local server. If the remote authentication succeeds the local connection
is also considered to be authenticated. The remote connection is closed as soon as the tagged
response from the ‘LOGIN’ command is received from the remote server.
The option parameter to the -O flag describes the remote server to forward authentication requests
to. hostname can be a hostname (imap.example.com) or a dotted-quad IP address (192.168.0.1). The
latter is useful if the remote server is multi-homed and has network interfaces that are unreachable
from the local IMAP server. The remote host is contacted on the ‘imap’ service port. A non-default
port can be specified by appending a slash and the port name or number to the hostname argument.
The -O flag and argument are mandatory when using the rimap mechanism.
shadow (AIX, Irix, Linux, Solaris)
Authenticate against the local "shadow password file". The exact mechanism is system dependent.
saslauthd currently understands the getspnam() and getuserpw() library routines. Some systems honour
the -T flag.
file included with the distribution for the list of available parameters.
sia (Digital UNIX)
Authenticate using the Digital UNIX Security Integration Architecture (a.k.a. "enhanced security").
NOTES
The kerberos4 authentication driver consumes considerable resources. To perform an authentication it must obtain
a ticket granting ticket from the TGT server on every authentication request. The Kerberos library routines that
obtain the TGT also create a local ticket file, on the reasonable assumption that you will want to save the TGT
for use by other Kerberos applications. These ticket files are unusable by saslauthd , however there is no way
not to create them. The overhead of creating and removing these ticket files can cause serious performance
degradation on busy servers. (Kerberos was never intended to be used in this manner, anyway.)
FILES
/run/saslauthd/mux The default communications socket.
/etc/saslauthd.conf
The default configuration file for ldap support.
SEE ALSO
passwd(1), getpwent(3), getspnam(3), getuserpw(3), sasl_checkpass(3) sia_authenticate_user(3),
CMU-SASL 12 12 2005 CMU-SASL
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