RFC 8461, "SMTP MTA Strict Transport Security (MTA-STS)", September 2018Source of RFC: uta (art)
Errata ID: 6285
Publication Format(s) : TEXT
Reported By: Paul Buonopane
Date Reported: 2020-09-10
Section 3.1 says:
sts-field-delim = *WSP ";" *WSP
It should say:
sts-field-delim = ";" *WSP
The following text appears within the same section:
> If multiple TXT records for "_mta-sts" are returned by the resolver, records that do not begin with "v=STSv1;" are discarded.
The current definition of sts-field-delim is incompatible with that instruction. Either the instruction needs to be changed, a new delimiter needs to be defined that doesn't permit whitespace before the semicolon, or sts-field-delim needs to be modified.