diff --git a/src/misc.c b/src/misc.c
index 26b94579..9643acdc 100644
--- a/src/misc.c
+++ b/src/misc.c
@@ -103,7 +103,7 @@ int searchStringInBuffer(char *s, int len1, char *what, int len2){
          return i;
    }
 
-   return 0;
+   return -1;
 }
 
 
diff --git a/src/smtp.c b/src/smtp.c
index 062f1ce9..5512ed73 100644
--- a/src/smtp.c
+++ b/src/smtp.c
@@ -72,18 +72,19 @@ void process_smtp_command(struct smtp_session *session, char *buf){
 
 void process_data(struct smtp_session *session, char *readbuf, int readlen){
    char puf[SMALLBUFSIZE+BIGBUFSIZE];
-   int n, pos, len;
+   int n, pos, len, writelen;
 
    memset(puf, 0, sizeof(puf));
+   len = readlen;
 
    if(session->buflen > 0){
       memcpy(&puf[0], session->buf, session->buflen);
       memcpy(&puf[session->buflen], readbuf, readlen);
-      len = session->buflen + readlen;
+
+      len += session->buflen;
    }
    else {
       memcpy(&puf[0], readbuf, readlen);
-      len = readlen;
    }
 
    pos = searchStringInBuffer(&puf[0], len, SMTP_CMD_PERIOD, 5);
@@ -93,27 +94,37 @@ void process_data(struct smtp_session *session, char *readbuf, int readlen){
          session->tot_len += pos;
          process_command_period(session);
       }
-      else syslog(LOG_PRIORITY, "ERROR: process_data(): failed to write %d bytes", pos);
+      else syslog(LOG_PRIORITY, "ERROR (line: %d): process_data(): failed to write %d bytes", __LINE__, pos);
    }
-   else {
+   else if(pos < 0){
       n = search_char_backward(&puf[0], len, '\r');
 
       if(n == -1 || len - n > 4){
-         if(write(session->fd, puf, len) != -1){
-            session->tot_len += len;
+
+         if(n == -1) writelen = len;
+         else writelen = n-1;
+
+         if(writelen > 0){
+            if(write(session->fd, puf, writelen) != -1){
+               session->tot_len += writelen;
+            }
+            else syslog(LOG_PRIORITY, "ERROR (line: %d): process_data(): failed to write %d bytes", __LINE__, writelen);
          }
-         else syslog(LOG_PRIORITY, "ERROR: process_data(): failed to write %d bytes", len);
       }
       else {
          if(write(session->fd, puf, n) != -1){
             session->tot_len += n;
          }
-         else syslog(LOG_PRIORITY, "process_data(): failed to write %d bytes", n);
+         else syslog(LOG_PRIORITY, "ERROR (line: %d) process_data(): failed to write %d bytes", __LINE__, n);
 
          snprintf(session->buf, SMALLBUFSIZE-1, "%s", &puf[n]);
          session->buflen = len - n;
       }
    }
+   else {
+      // The buffer contains only the CR-LF-DOT-CR-LF sequence
+      process_command_period(session);
+   }
 }
 
 
diff --git a/unit_tests/smtp.c b/unit_tests/smtp.c
index 9b43f830..d71a69b8 100644
--- a/unit_tests/smtp.c
+++ b/unit_tests/smtp.c
@@ -309,6 +309,56 @@ static void test_smtp_commands_starttls(char *server, int port, struct data *dat
 }
 
 
+static void test_smtp_commands_period_command_in_2_parts(char *server, int port, char *part1, char *part2, struct data *data){
+   char recvbuf[MAXBUFSIZE], sendbuf[MAXBUFSIZE];
+
+   connect_to_smtp_server(server, port, data);
+
+   send_helo_command(data->net);
+
+   send_smtp_command(data->net, "MAIL FROM: <sender@aaa.fu>\r\nRCPT TO: <archive@aaa.fu>\r\nDATA\r\n", recvbuf, sizeof(recvbuf)-1);
+   assert(strncmp(recvbuf, "250 ", 4) == 0 && "MAIL");
+
+   snprintf(sendbuf, sizeof(sendbuf)-1, "%s%s", testmessage, part1);
+   write1(data->net, sendbuf, strlen(sendbuf));
+
+   snprintf(sendbuf, sizeof(sendbuf), "%s", part2);
+   send_smtp_command(data->net, sendbuf, recvbuf, sizeof(recvbuf)-1);
+
+   snprintf(sendbuf, sizeof(sendbuf)-1, "QUIT\r\n");
+   send_smtp_command(data->net, sendbuf, recvbuf, sizeof(recvbuf)-1);
+
+   assert(strncmp(recvbuf, "250 ", 4) == 0 && "QUIT");
+
+   close(data->net->socket);
+}
+
+
+static void test_smtp_commands_period_command_in_its_own_packet(char *server, int port, struct data *data){
+   char recvbuf[MAXBUFSIZE], sendbuf[MAXBUFSIZE];
+
+   connect_to_smtp_server(server, port, data);
+
+   send_helo_command(data->net);
+
+   send_smtp_command(data->net, "MAIL FROM: <sender@aaa.fu>\r\nRCPT TO: <archive@aaa.fu>\r\nDATA\r\n", recvbuf, sizeof(recvbuf)-1);
+   assert(strncmp(recvbuf, "250 ", 4) == 0 && "MAIL");
+
+   snprintf(sendbuf, sizeof(sendbuf)-1, "%s", testmessage);
+   write1(data->net, sendbuf, strlen(sendbuf));
+
+   snprintf(sendbuf, sizeof(sendbuf), "\r\n.\r\n");
+   send_smtp_command(data->net, sendbuf, recvbuf, sizeof(recvbuf)-1);
+
+   snprintf(sendbuf, sizeof(sendbuf)-1, "QUIT\r\n");
+   send_smtp_command(data->net, sendbuf, recvbuf, sizeof(recvbuf)-1);
+
+   assert(strncmp(recvbuf, "250 ", 4) == 0 && "QUIT");
+
+   close(data->net->socket);
+}
+
+
 int main(int argc, char **argv){
    int c, port=25;
    char *server=NULL;
@@ -380,6 +430,11 @@ int main(int argc, char **argv){
    test_smtp_commands_with_reset_command(server, port, &data);
    test_smtp_commands_partial_command(server, port, &data);
    test_smtp_commands_partial_command_pipelining(server, port, &data);
+   test_smtp_commands_period_command_in_2_parts(server, port, "\r", "\n.\r\n", &data);
+   test_smtp_commands_period_command_in_2_parts(server, port, "\r\n", ".\r\n", &data);
+   test_smtp_commands_period_command_in_2_parts(server, port, "\r\n.", "\r\n", &data);
+   test_smtp_commands_period_command_in_2_parts(server, port, "\r\n.\r", "\n", &data);
+   test_smtp_commands_period_command_in_its_own_packet(server, port, &data);
 
    helo = 1; // we must use EHLO to get the STARTTLS in the response
    test_smtp_commands_starttls(server, port, &data);