---
name: "cyrus-pop3d"
section: "8"
platform: "linux"
package: "cyrus-pop3d"
version: "3.10.2-1+deb13u2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/cyrus-pop3d"
---

# cyrus-pop3d(8)

Cyrus IMAP documentation POP3 server process

## NAME

pop3d - Cyrus IMAP documentation

POP3 server process

## SYNOPSIS

```
pop3d [ -C config-file ] [ -U uses ] [ -T timeout ] [ -D ]
    [ -s ] [ -k ] [ -p ssf ]
```

## DESCRIPTION

**pop3d** *is an POP3 server.  It accepts commands on its standard* *input and responds on its standard output.  It MUST be invoked by* *[master(8)](/master/8.md) with those descriptors attached to a remote client* *connection.*

**pop3d** *reads its configuration options out of the [imapd.conf(5)](/imapd.conf/5.md) file unless specified otherwise by* **-C***.*

*If the directory* **log***/user exists under the directory specified in* *the* **configdirectory** *configuration option, then* **pop3d** *will create* *protocol telemetry logs for sessions authenticating as user.*

*The telemetry logs will be stored in the* **log***/user directory with* *a filename of the* **pop3d** *process-id.*

## OPTIONS

- **-C config-file**

  *Use the specified configuration file config-file rather than the default [imapd.conf(5)](/imapd.conf/5.md).*

- **-U uses**

  *The maximum number of times that the process should be used for new* *connections before shutting down.  The default is 250.*

- **-T timeout**

  *The number of seconds that the process will wait for a new* *connection before shutting down.  Note that a value of 0 (zero)* *will disable the timeout.  The default is 60.*

- **-D**

  *Run external debugger specified in debug\_command.*

- **-s**

  *Serve POP3 over SSL (pop3s).  All data to and from* **pop3d** *is* *encrypted using the Secure Sockets Layer.*

- **-k**

  *Serve MIT's KPOP (Kerberized POP) protocol instead.*

- **-p ssf**

  *Tell* **pop3d** *that an external layer exists.  An SSF (security* *strength factor) of 1 means an integrity protection layer exists.* *Any higher SSF implies some form of privacy protection.*

## EXAMPLES

**pop3d** *is commonly included in the SERVICES section of* *[cyrus.conf(5)](/cyrus.conf/5.md) like so:*

```
SERVICES {
    imap        cmd="imapd -U 30" listen="imap" prefork=0
    imaps       cmd="imapd -s -U 30" listen="imaps" prefork=0 maxchild=100
    pop3        cmd="pop3d -U 30" listen="pop3" prefork=0
    pop3s       cmd="pop3d -s -U 30" listen="pop3s" prefork=0 maxchild=100
    lmtpunix    cmd="lmtpd" listen="/var/run/cyrus/socket/lmtp" prefork=0 maxchild=20
    sieve       cmd="timsieved" listen="sieve" prefork=0
    notify      cmd="notifyd" listen="/var/run/cyrus/socket/notify" proto="udp" prefork=1
    httpd       cmd="httpd" listen=8080 prefork=1 maxchild=20
}
```

## FILES

**/etc/imapd.conf**

## SEE ALSO

*[imapd.conf(5)](/imapd.conf/5.md)***,** *[master(8)](/master/8.md)*

## AUTHOR

**The Cyrus Team, Nic Bernstein (Onlight)**

## COPYRIGHT

**1993–2025, The Cyrus Team**