
AP-5131 Access Point Product Reference Guide
6-52
3. Configure the SMTP field to disable or restrict specific kinds of network mail traffic.4. Configure the FTP field to block or restrict various FTP traffic on the network.Block Outbound SMTP 
Commands
Simple Mail Transport Protocol (SMTP) is the Internet standard for 
host-to-host mail transport. SMTP generally operates over TCP on 
port 25. SMTP filtering allows the blocking of any or all outgoing 
SMTP commands. Check the box next to the command to disable 
that command when using SMTP across the AP-5131’s WAN port.
• HELO - (Hello) Identifies the SMTP sender to the SMTP 
receiver.
• MAIL- Initiates a mail transaction where data is delivered to 
one or more mailboxes on the local server.
• RCPT: (Recipient) Identifies a recipient of mail data.
• DATA - Tells the SMTP receiver to treat the following 
information as mail data from the sender.
• QUIT - Tells the receiver to respond with an OK reply and 
terminate communication with the sender.
• SEND - Initiates a mail transaction where mail is sent to one 
or more remote terminals.
• SAML - (Send and Mail) Initiates a transaction where mail 
data is sent to one or more local mailboxes and remote 
terminals.
• RESET - Cancels mail transaction and informs the recipient 
to discard data sent during transaction. 
• VRFY - Asks receiver to confirm the specified argument 
identifies a user. If argument does identify a user, the full 
name and qualified mailbox is returned.
• EXPN - (Expand) Asks receiver to confirm a specified 
argument identifies a mailing list. If the argument identifies 
a list, the membership list of the mailing list is returned.