SMTP Load Balanciing - strange behaviour

Looks like you are talking successfully to an SMTP daemon. Can you see the traffic flowing via "bigtop -n" or through tcpdump?

 

 

Here's the basic code to send a manually crafted email. Some mail servers will enforce the angle brackets around addresses, and some will enforce proper host declarations during the ehlo/helo statement.

 

 

 
 telnet a.b.c.d 25 
 helo some.host 
 mail from:  
 rcpt to:  
 data: 
 subject: subject line 
 message text goes here 
 . 
 quit