MAX H ENTRIES

TCP/IP-channel-specific options: MAX_H_ENTRIES (integer)
New in MS 8.1. This TCP/IP channel SMTP server option specifies the maximum number of "J"   entries  to write during a single  SMTP connection session. The default is 10.

Note that keeping this value set to a reasonable size keeps the MTA from wasting too much time  writing "J" entries for VRFY and EXPN commands, so  that deliberate abuse of these commands will not distract the  MTA from more important work; i.e., it protects against a  certain form of "denial of service" attack.

When this limit is reached, the final "J" record for the session will contain (in addition to the "regular" text in a  "J" record) the extra text "(limit reached; last H  record for this session)".

See also:
 * MTA transaction log entry format
 * MTA counters
 * TCPIP-channel-specific options