E-Mail Analysis Engine
Similar to the SMTP protocol, the ESMTP agreement provides a basal adjustment for exchanging e-mail messages. ESMTP specifies
service extensions to the aboriginal SMTP agreement for sending e-mail letters that abutment graphics, audio, and video files,
and argument in assorted civic languages. Although an ESMTP affair is agnate to SMTP, there is one difference—the EHLO
command. An ESMTP applicant acknowledging ESMTP agreement starts a affiliation by arising the EHLO command instead of the
HELO command acclimated in accepted SMTP. (Refer to RFC 1869, "SMTP Service Extensions," for added details.)
The added SMTP analysis agent adds abutment for ESMTP, Post Office Agreement 3 (POP3), and Internet Message Access
Protocol (IMAP) in accession to the accepted SMTP protocol. Advanced appliance analysis prevents agreement masquerading
and administration austere RFC compliance.
To configure SMTP/ESMTP inspection, use the ip audit name inspection-name {smtp | esmtp } command from the
global agreement approach forth with added appropriate parameters. (Refer to accomplish authentic beforehand in the area "Configuring
CBAC .") This affection was alien in IOS Version 12.3(14)T.