The SMTP mail relay on a linux machine


D. Lyon

Why? A local relay will speed the transfer of e-mail from LAN based workstations by 100 times.

It will also enable unlimited numbers of people in large outgoing lists to be processed.

Finally, it frees up the workstations from the long e-mail chore and gives a central location for

e-mail administration.


If you have a router, make sure that it is in the host table as your gateway: gate

Run linuxconf as root.

Make sure your basic host information is correct:

Host name                  
                                  Adaptor 1
                                  [X] Enabled                   
            Config mode           (o) Manual ( ) Dhcp ( ) Bootp 
            Primary name + domain               
            Aliases (opt)         lyon www                      
            IP address                   
            Netmask (opt)                
            Net device            eth0                         
            Kernel module         3c509                        
            I/O port (opt)        
Note that the IP address of the SMTP machine is non-routable and is 
generally available only on the private net. This disables the spammers
from finding it as a spam relay.
As a result, you can disable relay control, which enables it
for the private office.
 Mail delivery system (sendmail)       
 Present your system as                         
                                   [X] Accept email for    
     Mail server                                                       
     Mail gateway                                                      
     Mail gateway protocol         smtp                               
                                   [ ] match full user name            
                                   [ ] Enable relay control (spammers)
     Messages size limit           (o) No limit __________            
                                   [ ] Don't try to deliver immediatly 
     Process queue every (minutes) 1                                   
                                   [ ] Use special shell smrsh        
     Maximum recipients per msg.   (o) Defaults __________             
                                   DNS features
                                   [ ] wait for DNS
No, DON'T Enable Relay control, unless your machine is visible
to the outside world. If you enable control, other machines
in the office will not be able to relay with the linux machine.
If you disable control, make sure your machine is NOT
accessable from the outside world (block the spammers!)...