How can I use Postfix to track/log the HELO name that IPs are communicating to it with

Wietse Venema (author of Postfix) gave this answer to a question asked in 2012 on the postfix-users mailinglist:

warn_if_reject check_helo_access static:reject

It is probably current, give it a try.

Update

I gave it a try:

First of all the configuration needs to be made in the smtpd_helo_restrictions configuration directive.

smtpd_helo_restrictions = warn_if_reject check_helo_access static:reject

This will result in log entries of the following sort:

Oct 16 00:12:45 vega postfix/smtpd[6676]: NOQUEUE: reject_warning: RCPT from unknown[xxxx:xxxx:xxxx::x]: 554 5.7.1 <test>: Helo command rejected: Access denied; from=<[email protected]> to=<[email protected]> proto=SMTP helo=<test>

In this case I used test in the HELO command of the SMTP connection. With this being a reject_warning, pflogsumm will have probably no problem summarizing this.