How do I register an ipv6 mailhost?
Trying to parse https://www.spamcop.net/sc?id=z6437551039z397c7682b607208ad3137a9ddf74157ez
host 2002:a17:902:6881:0:0:0:0 (getting name) no name
0: Received: by 2002:a17:902:6881:: with SMTP id i1-v6mr7121788plk.323.1516767567431; Tue, 23 Jan 2018 20:19:27 -0800 (PST)
No unique hostname found for source: 2002:a17:902:6881:0:0:0:0
Possible forgery. Supposed receiving system not associated with any of your mailhosts
Will not trust this Received line.
Mailhost configuration problem, identified internal IP as source
Please correct this situation - register every email address where you receive spam
No source IP address found, cannot proceed.
Experiment shows that removing only the "X-Received: by 2002: (etc.)" line ("line" in email headers sense of course, i.e. including any indented continuation lines following it) is enough to make SpamCop parse the spam with no error. (Then I paste the removed line back, of course, into the first "user comments" box at the end of the parse page.)