1 files changed, 16 insertions, 0 deletions

diff --git a/plugins/check_smtp.c b/plugins/check_smtp.c
index 2000c62..2d2e289 100644
--- a/plugins/check_smtp.c
+++ b/plugins/check_smtp.c
@@ -43,6 +43,8 @@
 
 #define SMTP_PORT       25
 #define SMTP_EXPECT     "220"
+#define SMTP_HELO "HELO "
+
 /* sendmail will syslog a "NOQUEUE" error if session does not attempt
  * to do something useful. This can be prevented by giving a command
  * even if syntax is illegal (MAIL requires a FROM:<...> argument)
@@ -74,10 +76,18 @@ main (int argc, char **argv)
         int sd;
         int result;
         char buffer[MAX_INPUT_BUFFER] = "";
+        char helocmd[255] = SMTP_HELO ;
+        char myhostname[248];
+        
 
         if (process_arguments (argc, argv) != OK)
                 usage ("Invalid command arguments supplied\n");
 
+        /* initalize the HELO command with the localhostname */
+        gethostname(myhostname, sizeof(myhostname));
+        strcat(helocmd, myhostname);
+        strcat(helocmd, "\r\n");
+        
         /* initialize alarm signal handling */
         signal (SIGALRM, socket_timeout_alarm_handler);
 
@@ -138,12 +148,18 @@ main (int argc, char **argv)
                 }
 
                 /* close the connection */
+                /* first send the HELO command */
+                send(sd,helocmd,strlen(helocmd),0);
+                /* allow for response to helo command to reach us */
+                recv(sd,buffer,MAX_INPUT_BUFFER-1,0);
+                                
 #ifdef SMTP_USE_DUMMYCMD
                send(sd,SMTP_DUMMYCMD,strlen(SMTP_DUMMYCMD),0);
                /* allow for response to DUMMYCMD to reach us */
                recv(sd,buffer,MAX_INPUT_BUFFER-1,0);
 #endif /* SMTP_USE_DUMMYCMD */
 
+                /* finally close the connection */
                 send (sd, SMTP_QUIT, strlen (SMTP_QUIT), 0);
                 close (sd);
         }