new file mode 100644
--- /dev/null
+++ b/src/mail/ngx_mail_pop3_module.c
@@ -0,0 +1,263 @@
+
+/*
+ * Copyright (C) Igor Sysoev
+ */
+
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+#include <ngx_event.h>
+#include <ngx_mail.h>
+#include <ngx_mail_pop3_module.h>
+
+
+static void *ngx_mail_pop3_create_srv_conf(ngx_conf_t *cf);
+static char *ngx_mail_pop3_merge_srv_conf(ngx_conf_t *cf, void *parent,
+    void *child);
+
+
+static ngx_str_t  ngx_mail_pop3_default_capabilities[] = {
+    ngx_string("TOP"),
+    ngx_string("USER"),
+    ngx_string("UIDL"),
+    ngx_null_string
+};
+
+
+static ngx_conf_bitmask_t  ngx_mail_pop3_auth_methods[] = {
+    { ngx_string("plain"), NGX_MAIL_AUTH_PLAIN_ENABLED },
+    { ngx_string("apop"), NGX_MAIL_AUTH_APOP_ENABLED },
+    { ngx_string("cram-md5"), NGX_MAIL_AUTH_CRAM_MD5_ENABLED },
+    { ngx_null_string, 0 }
+};
+
+
+static ngx_str_t  ngx_mail_pop3_auth_plain_capability =
+    ngx_string("+OK methods supported:" CRLF
+               "LOGIN" CRLF
+               "PLAIN" CRLF
+               "." CRLF);
+
+
+static ngx_str_t  ngx_mail_pop3_auth_cram_md5_capability =
+    ngx_string("+OK methods supported:" CRLF
+               "LOGIN" CRLF
+               "PLAIN" CRLF
+               "CRAM-MD5" CRLF
+               "." CRLF);
+
+
+static ngx_mail_protocol_t  ngx_mail_pop3_protocol = {
+    ngx_string("pop3"),
+    { 110, 995, 0, 0 },
+    NGX_MAIL_POP3_PROTOCOL,
+
+    ngx_mail_pop3_init_session,
+    ngx_mail_pop3_init_protocol,
+    ngx_mail_pop3_parse_command,
+    ngx_mail_pop3_auth_state,
+
+    ngx_string("-ERR internal server error" CRLF)
+};
+
+
+static ngx_command_t  ngx_mail_pop3_commands[] = {
+
+    { ngx_string("pop3_capabilities"),
+      NGX_MAIL_MAIN_CONF|NGX_MAIL_SRV_CONF|NGX_CONF_1MORE,
+      ngx_mail_capabilities,
+      NGX_MAIL_SRV_CONF_OFFSET,
+      offsetof(ngx_mail_pop3_srv_conf_t, capabilities),
+      NULL },
+
+    { ngx_string("pop3_auth"),
+      NGX_MAIL_MAIN_CONF|NGX_MAIL_SRV_CONF|NGX_CONF_1MORE,
+      ngx_conf_set_bitmask_slot,
+      NGX_MAIL_SRV_CONF_OFFSET,
+      offsetof(ngx_mail_pop3_srv_conf_t, auth_methods),
+      &ngx_mail_pop3_auth_methods },
+
+      ngx_null_command
+};
+
+
+static ngx_mail_module_t  ngx_mail_pop3_module_ctx = {
+    &ngx_mail_pop3_protocol,               /* protocol */
+
+    NULL,                                  /* create main configuration */
+    NULL,                                  /* init main configuration */
+
+    ngx_mail_pop3_create_srv_conf,         /* create server configuration */
+    ngx_mail_pop3_merge_srv_conf           /* merge server configuration */
+};
+
+
+ngx_module_t  ngx_mail_pop3_module = {
+    NGX_MODULE_V1,
+    &ngx_mail_pop3_module_ctx,             /* module context */
+    ngx_mail_pop3_commands,                /* module directives */
+    NGX_MAIL_MODULE,                       /* module type */
+    NULL,                                  /* init master */
+    NULL,                                  /* init module */
+    NULL,                                  /* init process */
+    NULL,                                  /* init thread */
+    NULL,                                  /* exit thread */
+    NULL,                                  /* exit process */
+    NULL,                                  /* exit master */
+    NGX_MODULE_V1_PADDING
+};
+
+
+static void *
+ngx_mail_pop3_create_srv_conf(ngx_conf_t *cf)
+{
+    ngx_mail_pop3_srv_conf_t  *pscf;
+
+    pscf = ngx_pcalloc(cf->pool, sizeof(ngx_mail_pop3_srv_conf_t));
+    if (pscf == NULL) {
+        return NULL;
+    }
+
+    if (ngx_array_init(&pscf->capabilities, cf->pool, 4, sizeof(ngx_str_t))
+        != NGX_OK)
+    {
+        return NULL;
+    }
+
+    return pscf;
+}
+
+
+static char *
+ngx_mail_pop3_merge_srv_conf(ngx_conf_t *cf, void *parent, void *child)
+{
+    ngx_mail_pop3_srv_conf_t *prev = parent;
+    ngx_mail_pop3_srv_conf_t *conf = child;
+
+    u_char      *p;
+    size_t       size, stls_only_size;
+    ngx_str_t   *c, *d;
+    ngx_uint_t   i;
+
+    ngx_conf_merge_bitmask_value(conf->auth_methods,
+                                 prev->auth_methods,
+                                 (NGX_CONF_BITMASK_SET
+                                  |NGX_MAIL_AUTH_PLAIN_ENABLED));
+
+    if (conf->capabilities.nelts == 0) {
+        conf->capabilities = prev->capabilities;
+    }
+
+    if (conf->capabilities.nelts == 0) {
+
+        for (d = ngx_mail_pop3_default_capabilities; d->len; d++) {
+            c = ngx_array_push(&conf->capabilities);
+            if (c == NULL) {
+                return NGX_CONF_ERROR;
+            }
+
+            *c = *d;
+        }
+    }
+
+    size = sizeof("+OK Capability list follows" CRLF) - 1
+           + sizeof("." CRLF) - 1;
+
+    stls_only_size = size + sizeof("STLS" CRLF) - 1;
+
+    c = conf->capabilities.elts;
+    for (i = 0; i < conf->capabilities.nelts; i++) {
+        size += c[i].len + sizeof(CRLF) - 1;
+
+        if (ngx_strcasecmp(c[i].data, (u_char *) "USER") == 0) {
+            continue;
+        }
+
+        stls_only_size += c[i].len + sizeof(CRLF) - 1;
+    }
+
+    if (conf->auth_methods & NGX_MAIL_AUTH_CRAM_MD5_ENABLED) {
+        size += sizeof("SASL LOGIN PLAIN CRAM-MD5" CRLF) - 1;
+
+    } else {
+        size += sizeof("SASL LOGIN PLAIN" CRLF) - 1;
+    }
+
+    p = ngx_palloc(cf->pool, size);
+    if (p == NULL) {
+        return NGX_CONF_ERROR;
+    }
+
+    conf->capability.len = size;
+    conf->capability.data = p;
+
+    p = ngx_cpymem(p, "+OK Capability list follows" CRLF,
+                   sizeof("+OK Capability list follows" CRLF) - 1);
+
+    for (i = 0; i < conf->capabilities.nelts; i++) {
+        p = ngx_cpymem(p, c[i].data, c[i].len);
+        *p++ = CR; *p++ = LF;
+    }
+
+    if (conf->auth_methods & NGX_MAIL_AUTH_CRAM_MD5_ENABLED) {
+        p = ngx_cpymem(p, "SASL LOGIN PLAIN CRAM-MD5" CRLF,
+                       sizeof("SASL LOGIN PLAIN CRAM-MD5" CRLF) - 1);
+
+    } else {
+        p = ngx_cpymem(p, "SASL LOGIN PLAIN" CRLF,
+                       sizeof("SASL LOGIN PLAIN" CRLF) - 1);
+    }
+
+    *p++ = '.'; *p++ = CR; *p = LF;
+
+
+    size += sizeof("STLS" CRLF) - 1;
+
+    p = ngx_palloc(cf->pool, size);
+    if (p == NULL) {
+        return NGX_CONF_ERROR;
+    }
+
+    conf->starttls_capability.len = size;
+    conf->starttls_capability.data = p;
+
+    p = ngx_cpymem(p, conf->capability.data,
+                   conf->capability.len - (sizeof("." CRLF) - 1));
+
+    p = ngx_cpymem(p, "STLS" CRLF, sizeof("STLS" CRLF) - 1);
+    *p++ = '.'; *p++ = CR; *p = LF;
+
+
+    if (conf->auth_methods & NGX_MAIL_AUTH_CRAM_MD5_ENABLED) {
+        conf->auth_capability = ngx_mail_pop3_auth_cram_md5_capability;
+
+    } else {
+        conf->auth_capability = ngx_mail_pop3_auth_plain_capability;
+    }
+
+
+    p = ngx_palloc(cf->pool, stls_only_size);
+    if (p == NULL) {
+        return NGX_CONF_ERROR;
+    }
+
+    conf->starttls_only_capability.len = stls_only_size;
+    conf->starttls_only_capability.data = p;
+
+    p = ngx_cpymem(p, "+OK Capability list follows" CRLF,
+                   sizeof("+OK Capability list follows" CRLF) - 1);
+
+    for (i = 0; i < conf->capabilities.nelts; i++) {
+        if (ngx_strcasecmp(c[i].data, (u_char *) "USER") == 0) {
+            continue;
+        }
+
+        p = ngx_cpymem(p, c[i].data, c[i].len);
+        *p++ = CR; *p++ = LF;
+    }
+
+    p = ngx_cpymem(p, "STLS" CRLF, sizeof("STLS" CRLF) - 1);
+    *p++ = '.'; *p++ = CR; *p = LF;
+
+    return NGX_CONF_OK;
+}