--- a/src/imap/ngx_imap_proxy_module.c
+++ b/src/imap/ngx_imap_proxy_module.c
@@ -17,16 +17,23 @@ typedef struct {
 
 
 static void ngx_imap_proxy_block_read(ngx_event_t *rev);
-static void ngx_imap_proxy_auth_handler(ngx_event_t *rev);
+static void ngx_imap_proxy_imap_handler(ngx_event_t *rev);
+static void ngx_imap_proxy_pop3_handler(ngx_event_t *rev);
 static void ngx_imap_proxy_dummy_handler(ngx_event_t *ev);
-static ngx_int_t ngx_imap_proxy_read_response(ngx_imap_session_t *s);
+static ngx_int_t ngx_imap_proxy_read_response(ngx_imap_session_t *s,
+    ngx_uint_t what);
 static void ngx_imap_proxy_handler(ngx_event_t *ev);
+static void ngx_imap_proxy_internal_server_error(ngx_imap_session_t *s);
 static void ngx_imap_proxy_close_session(ngx_imap_session_t *s);
 static void *ngx_imap_proxy_create_conf(ngx_conf_t *cf);
 static char *ngx_imap_proxy_merge_conf(ngx_conf_t *cf, void *parent,
     void *child);
 
 
+#define NGX_IMAP_WAIT_OK    0
+#define NGX_IMAP_WAIT_NEXT  1
+
+
 static ngx_command_t  ngx_imap_proxy_commands[] = {
     { ngx_string("proxy"),
       NGX_IMAP_MAIN_CONF|NGX_IMAP_SRV_CONF|NGX_CONF_FLAG,
@@ -61,12 +68,13 @@ ngx_module_t  ngx_imap_proxy_module = {
 void
 ngx_imap_proxy_init(ngx_imap_session_t *s, ngx_peers_t *peers)
 {
-    ngx_int_t              rc;
-    ngx_imap_proxy_ctx_t  *p;
+    ngx_int_t                  rc;
+    ngx_imap_proxy_ctx_t      *p;
+    ngx_imap_core_srv_conf_t  *cscf;
 
     p = ngx_pcalloc(s->connection->pool, sizeof(ngx_imap_proxy_ctx_t));
     if (p == NULL) {
-        ngx_imap_close_connection(s->connection);
+        ngx_imap_session_internal_server_error(s);
         return;
     }
 
@@ -79,16 +87,27 @@ ngx_imap_proxy_init(ngx_imap_session_t *
     rc = ngx_event_connect_peer(&p->upstream);
 
     if (rc == NGX_ERROR) {
-        ngx_imap_proxy_close_session(s);
+        ngx_imap_session_internal_server_error(s);
         return;
     }
 
+    cscf = ngx_imap_get_module_srv_conf(s, ngx_imap_core_module);
+    ngx_add_timer(p->upstream.connection->read, cscf->timeout);
+
     p->upstream.connection->data = s;
     p->upstream.connection->pool = s->connection->pool;
 
     s->connection->read->handler = ngx_imap_proxy_block_read;
-    p->upstream.connection->read->handler = ngx_imap_proxy_auth_handler;
     p->upstream.connection->write->handler = ngx_imap_proxy_dummy_handler;
+
+    if (s->protocol == NGX_IMAP_POP3_PROTOCOL) {
+        p->upstream.connection->read->handler = ngx_imap_proxy_pop3_handler;
+        s->imap_state = ngx_pop3_start;
+
+    } else {
+        p->upstream.connection->read->handler = ngx_imap_proxy_imap_handler;
+        s->imap_state = ngx_imap_start;
+    }
 }
 
 
@@ -110,53 +129,189 @@ ngx_imap_proxy_block_read(ngx_event_t *r
 
 
 static void
-ngx_imap_proxy_auth_handler(ngx_event_t *rev)
+ngx_imap_proxy_imap_handler(ngx_event_t *rev)
 {
-    u_char              *p;
-    ngx_int_t            rc;
-    ngx_str_t            line;
-    ngx_connection_t    *c;
-    ngx_imap_session_t  *s;
+    u_char                    *p;
+    ngx_int_t                  rc;
+    ngx_str_t                  line;
+    ngx_connection_t          *c;
+    ngx_imap_session_t        *s;
+    ngx_imap_core_srv_conf_t  *cscf;
 
-    ngx_log_debug0(NGX_LOG_DEBUG_IMAP, rev->log, 0, "imap proxy auth handler");
+    ngx_log_debug0(NGX_LOG_DEBUG_IMAP, rev->log, 0,
+                   "imap proxy imap auth handler");
 
     c = rev->data;
     s = c->data;
 
     if (rev->timedout) {
-        ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT, "client timed out");
-        ngx_imap_proxy_close_session(s);
+        ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT,
+                      "upstream timed out");
+        ngx_imap_proxy_internal_server_error(s);
         return;
     }
 
     if (s->proxy->buffer == NULL) {
-        s->proxy->buffer = ngx_create_temp_buf(c->pool, /* STUB */ 4096);
+        cscf = ngx_imap_get_module_srv_conf(s, ngx_imap_core_module);
+
+        s->proxy->buffer = ngx_create_temp_buf(c->pool,
+                                               cscf->proxy_buffer_size);
         if (s->proxy->buffer == NULL) {
-            ngx_imap_proxy_close_session(s);
+            ngx_imap_proxy_internal_server_error(s);
             return;
         }
     }
 
-    rc = ngx_imap_proxy_read_response(s);
+    rc = ngx_imap_proxy_read_response(s, s->imap_state == ngx_imap_start ?
+                                      NGX_IMAP_WAIT_OK : NGX_IMAP_WAIT_NEXT);
 
     if (rc == NGX_AGAIN) {
         return;
     }
 
     if (rc == NGX_ERROR) {
-        /* TODO: ngx_imap_proxy_finalize_session(s, NGX_IMAP_INTERNAL_ERROR) */
-        ngx_imap_proxy_close_session(s);
+        ngx_imap_proxy_internal_server_error(s);
         return;
     }
 
-    if (s->imap_state == ngx_pop3_start) {
+    switch (s->imap_state) {
+
+    case ngx_imap_start:
+        ngx_log_debug0(NGX_LOG_DEBUG_IMAP, rev->log, 0,
+                       "imap proxy send login");
 
+        line.len = s->tag.len + sizeof("LOGIN ") - 1
+                   + 1 + NGX_SIZE_T_LEN + 1 + 2;
+        line.data = ngx_palloc(c->pool, line.len);
+        if (line.data == NULL) {
+            ngx_imap_proxy_internal_server_error(s);
+            return;
+        }
+
+        line.len = ngx_sprintf(line.data, "%VLOGIN {%uz}" CRLF,
+                               &s->tag, s->login.len)
+                   - line.data;
+
+        s->imap_state = ngx_imap_login;
+        break;
+
+    case ngx_imap_login:
         ngx_log_debug0(NGX_LOG_DEBUG_IMAP, rev->log, 0, "imap proxy send user");
 
-        line.len = sizeof("USER ") + s->login.len - 1 + 2;
+        line.len = s->login.len + 1 + NGX_SIZE_T_LEN + 1 + 2;
+        line.data = ngx_palloc(c->pool, line.len);
+        if (line.data == NULL) {
+            ngx_imap_proxy_internal_server_error(s);
+            return;
+        }
+
+        line.len = ngx_sprintf(line.data, "%V{%uz}" CRLF,
+                               &s->login, s->passwd.len)
+                   - line.data;
+
+        s->imap_state = ngx_imap_user;
+        break;
+
+    case ngx_imap_user:
+        ngx_log_debug0(NGX_LOG_DEBUG_IMAP, rev->log, 0,
+                       "imap proxy send passwd");
+
+        line.len = s->passwd.len + 2;
         line.data = ngx_palloc(c->pool, line.len);
         if (line.data == NULL) {
-            ngx_imap_proxy_close_session(s);
+            ngx_imap_proxy_internal_server_error(s);
+            return;
+        }
+
+        p = ngx_cpymem(line.data, s->passwd.data, s->passwd.len);
+        *p++ = CR; *p = LF;
+
+        s->imap_state = ngx_imap_passwd;
+        break;
+
+    default:
+#if (NGX_SUPPRESS_WARN)
+        line.len = 0;
+        line.data = NULL;
+#endif
+        break;
+    }
+
+    if (ngx_send(c, line.data, line.len) < (ssize_t) line.len) {
+        /*
+         * we treat the incomplete sending as NGX_ERROR
+         * because it is very strange here
+         */
+        ngx_imap_proxy_internal_server_error(s);
+        return;
+    }
+
+    s->proxy->buffer->pos = s->proxy->buffer->start;
+    s->proxy->buffer->last = s->proxy->buffer->start;
+
+    if (s->imap_state == ngx_imap_passwd) {
+        s->connection->read->handler = ngx_imap_proxy_handler;
+        s->connection->write->handler = ngx_imap_proxy_handler;
+        rev->handler = ngx_imap_proxy_handler;
+        c->write->handler = ngx_imap_proxy_handler;
+    }
+}
+
+
+static void
+ngx_imap_proxy_pop3_handler(ngx_event_t *rev)
+{
+    u_char                    *p;
+    ngx_int_t                  rc;
+    ngx_str_t                  line;
+    ngx_connection_t          *c;
+    ngx_imap_session_t        *s;
+    ngx_imap_core_srv_conf_t  *cscf;
+
+    ngx_log_debug0(NGX_LOG_DEBUG_IMAP, rev->log, 0,
+                   "imap proxy pop3 auth handler");
+
+    c = rev->data;
+    s = c->data;
+
+    if (rev->timedout) {
+        ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT,
+                      "upstream timed out");
+        ngx_imap_proxy_internal_server_error(s);
+        return;
+    }
+
+    if (s->proxy->buffer == NULL) {
+        cscf = ngx_imap_get_module_srv_conf(s, ngx_imap_core_module);
+
+        s->proxy->buffer = ngx_create_temp_buf(c->pool,
+                                               cscf->proxy_buffer_size);
+        if (s->proxy->buffer == NULL) {
+            ngx_imap_proxy_internal_server_error(s);
+            return;
+        }
+    }
+
+    rc = ngx_imap_proxy_read_response(s, NGX_IMAP_WAIT_OK);
+
+    if (rc == NGX_AGAIN) {
+        return;
+    }
+
+    if (rc == NGX_ERROR) {
+        ngx_imap_proxy_internal_server_error(s);
+        return;
+    }
+
+    switch (s->imap_state) {
+
+    case ngx_pop3_start:
+        ngx_log_debug0(NGX_LOG_DEBUG_IMAP, rev->log, 0, "imap proxy send user");
+
+        line.len = sizeof("USER ")  - 1 + s->login.len + 2;
+        line.data = ngx_palloc(c->pool, line.len);
+        if (line.data == NULL) {
+            ngx_imap_proxy_internal_server_error(s);
             return;
         }
 
@@ -164,52 +319,52 @@ ngx_imap_proxy_auth_handler(ngx_event_t 
         p = ngx_cpymem(p, s->login.data, s->login.len);
         *p++ = CR; *p = LF;
 
-        if (ngx_send(c, line.data, line.len) < (ssize_t) line.len) {
-            /*
-             * we treat the incomplete sending as NGX_ERROR
-             * because it is very strange here
-             */
-            ngx_imap_close_connection(c);
+        s->imap_state = ngx_pop3_user;
+        break;
+
+    case ngx_pop3_user:
+        ngx_log_debug0(NGX_LOG_DEBUG_IMAP, rev->log, 0, "imap proxy send pass");
+
+        line.len = sizeof("PASS ")  - 1 + s->passwd.len + 2;
+        line.data = ngx_palloc(c->pool, line.len);
+        if (line.data == NULL) {
+            ngx_imap_proxy_internal_server_error(s);
             return;
         }
 
-        s->imap_state = ngx_pop3_user;
-
-        s->proxy->buffer->pos = s->proxy->buffer->start;
-        s->proxy->buffer->last = s->proxy->buffer->start;
+        p = ngx_cpymem(line.data, "PASS ", sizeof("PASS ") - 1);
+        p = ngx_cpymem(p, s->passwd.data, s->passwd.len);
+        *p++ = CR; *p = LF;
 
-        return;
-    }
-
-    ngx_log_debug0(NGX_LOG_DEBUG_IMAP, rev->log, 0, "imap proxy send pass");
+        s->imap_state = ngx_pop3_passwd;
+        break;
 
-    line.len = sizeof("PASS ") + s->passwd.len - 1 + 2;
-    line.data = ngx_palloc(c->pool, line.len);
-    if (line.data == NULL) {
-        ngx_imap_proxy_close_session(s);
-        return;
+    default:
+#if (NGX_SUPPRESS_WARN)
+        line.len = 0;
+        line.data = NULL;
+#endif
+        break;
     }
 
-    p = ngx_cpymem(line.data, "PASS ", sizeof("PASS ") - 1);
-    p = ngx_cpymem(p, s->passwd.data, s->passwd.len);
-    *p++ = CR; *p = LF;
-
     if (ngx_send(c, line.data, line.len) < (ssize_t) line.len) {
         /*
          * we treat the incomplete sending as NGX_ERROR
          * because it is very strange here
          */
-        ngx_imap_close_connection(c);
+        ngx_imap_proxy_internal_server_error(s);
         return;
     }
 
     s->proxy->buffer->pos = s->proxy->buffer->start;
     s->proxy->buffer->last = s->proxy->buffer->start;
 
-    s->connection->read->handler = ngx_imap_proxy_handler;
-    s->connection->write->handler = ngx_imap_proxy_handler;
-    rev->handler = ngx_imap_proxy_handler;
-    c->write->handler = ngx_imap_proxy_handler;
+    if (s->imap_state == ngx_pop3_passwd) {
+        s->connection->read->handler = ngx_imap_proxy_handler;
+        s->connection->write->handler = ngx_imap_proxy_handler;
+        rev->handler = ngx_imap_proxy_handler;
+        c->write->handler = ngx_imap_proxy_handler;
+    }
 }
 
 
@@ -221,7 +376,7 @@ ngx_imap_proxy_dummy_handler(ngx_event_t
 
 
 static ngx_int_t
-ngx_imap_proxy_read_response(ngx_imap_session_t *s)
+ngx_imap_proxy_read_response(ngx_imap_session_t *s, ngx_uint_t what)
 {
     u_char     *p;
     ssize_t     n;
@@ -259,17 +414,31 @@ ngx_imap_proxy_read_response(ngx_imap_se
 
     p = b->pos;
 
-    if (p[0] == '+' && p[1] == 'O' && p[2] == 'K') {
-        return NGX_OK;
-    }
+    if (s->protocol == NGX_IMAP_POP3_PROTOCOL) {
+        if (p[0] == '+' && p[1] == 'O' && p[2] == 'K') {
+            return NGX_OK;
+        }
+
+        if (p[0] == '-' && p[1] == 'E' && p[2] == 'R' && p[3] == 'R') {
+            return NGX_IMAP_PROXY_ERROR;
+        }
 
-    if (p[0] == '-' && p[1] == 'E' && p[2] == 'R' && p[3] == 'R') {
-        return NGX_IMAP_PROXY_ERROR;
+    } else {
+        if (what == NGX_IMAP_WAIT_OK) {
+            if (p[0] == '*' && p[1] == ' ' && p[2] == 'O' && p[3] == 'K') {
+                return NGX_OK;
+            }
+
+        } else {
+            if (p[0] == '+' && p[1] == ' ' && p[2] == 'O' && p[3] == 'K') {
+                return NGX_OK;
+            }
+        }
     }
 
     *(b->last - 2) = '\0';
     ngx_log_error(NGX_LOG_ERR, s->connection->log, 0,
-                  "upstream sent invalid greeting line: \"%s\"", p);
+                  "upstream sent invalid response: \"%s\"", p);
 
     return NGX_IMAP_PROXY_INVALID;
 }
@@ -397,6 +566,21 @@ ngx_imap_proxy_handler(ngx_event_t *ev)
 
 
 static void
+ngx_imap_proxy_internal_server_error(ngx_imap_session_t *s)
+{
+    if (s->proxy->upstream.connection) {
+        ngx_log_debug1(NGX_LOG_DEBUG_IMAP, s->connection->log, 0,
+                       "close imap proxy connection: %d",
+                       s->proxy->upstream.connection->fd);
+
+        ngx_close_connection(s->proxy->upstream.connection);
+    }
+
+    ngx_imap_session_internal_server_error(s);
+}
+
+
+static void
 ngx_imap_proxy_close_session(ngx_imap_session_t *s)
 {
     if (s->proxy->upstream.connection) {