docs/modules/servers/partials/configure/server.adoc

The XML elements of all servers have an optional attribute `enabled` which defaults to `true`.

.Common configuration options for servers (SMTP, LMTP, POP3, IMAP, Managesieve)
|===
| Property Name | Explanation

| `bind`
| The option describes which IPv4 addresses and ports the server should bind to.
IPv6 addresses are not supported.
It is an optional, comma-separated list of `<IPv4>:<port>` tuples.
The default value is the IPv4 address `0.0.0.0` with the default port of the protocol
(24 for LMTP, 25 for SMTP, 110 for POP3, 143 for IMAP, and 4190 for Managesieve).

| `jmxName`
| An optional name for the JMX of this server.
The default value is `lmtpserver` for LMTP, `smtpserver` for SMTP, `pop3server` for POP3, `imapserver` for IMAP, and `managesieveserver` for Managesieve.

| `ioWorkerCount`
| Sets the maximum number of IO threads.
IO threads are responsible for receiving incoming messages and framing them
(split line by line).
IO threads also take care of compression and TLS.
Their tasks are short-lived and non-blocking.
It is an optional integer and defaults to 2 times the number of CPUs.

| `bossWorkerCount`
| Sets the maximum number of boss threads.
Boss threads are responsible for accepting incoming connections and initializing associated resources.
It is an optional integer.
By default, boss threads are not used and and IO threads handle their tasks.

| `maxExecutorCount`
| Sets the maximum number of worker threads.
Worker threads takes care of potentially blocking tasks like executing commands.
It is an optional integer which defaults to 16.

| `helloName`
| Defines the server name used in the initial server greeting.
By default, Java libraries are used to get the local hostname.
If that fails, `localhost` is used.
If the element is present and the attribute `autodetect` is set to `false`, the body of this element is used instead.

| `connectiontimeout`
| Sets the timeout for connection in seconds.
It is an optional integer with the default value 300.

| `connectionBacklog`
| Sets the maximum number of queued connection requests (backlog).
It is an optional integer which defaults to 200.

| `connectionLimit`
| Sets the maximum number of simultaneous incoming connections.
It is an optional, positive integer.
If not configured, there is no limit.

| `connectionLimitPerIP`
| Sets the maximum number of simultaneous incoming connections per client IP.
It is an optional, positive integer.
If not configured, there is no limit.

| `tls`
| Configures implicit TLS and STARTTLS.
The configuration is described in more detail xref:{pages-path}/configure/ssl.adoc[here].

| `gracefulShutdown`
| If `true`, the server attempts a graceful shutdown, which is safer but can take time.
It is a boolean that defaults to `true`.

| `useEpoll`
| If `true`, the server uses the native EPOLL implementation for Netty, otherwise it uses NIO.
It is a boolean that defaults to `false`.

| `highWriteBufferWaterMark`, `lowWriteBufferWaterMark`
| Configures a water mark for Netty's write buffer.
If none of the two elements is present, no water mark is set and Netty's defaults apply.
If only one of them is provided, both the high and the low water mark are set to that value.
The last character of the value may be a unit.
Supported units are `B` for bytes, `K` for kibibyte (1,024 bytes), `M` for mebibyte (1,024 kibibytes), and `G` for gibibyte (1,024 mebibytes).
If no unit is given, the value is interpreted as bytes.

| `proxyRequired`
| Enables HAProxy's PROXY protocol for incoming connections.
PROXY protocol allows a reverse proxy in front of the email server to provide information about the original TCP connection.
This is most relevant for getting the real IP address of the client.
If this is enabled, all connections are **required** to use the PROXY protocol.
It is a boolean that defaults to `false`.

| `proxyFirst`
| Configures the order of encapsulation of TLS and PROXY protocol.
If `true`, the server expects a PROXY protocol header first and TLS records (if enabled) after that.
This means the reverse proxy transparently proxies TCP connections and does not touch the TLS connection between client and email server.
If `false`, the server expects TLS records (if enabled) that contain a proxied connection.
This means the TLS connection is established between reverse proxy and email server.
It is a boolean that defaults to `true`.

|===