4 ms·
Right. SMTP header lines can't exceed 998 characters, but RFC2822 now allows multi-line headers[1], so there's no limit except one that might be imposed by an M
by jamiesonbecker 10y ago
Right. SMTP header lines can't exceed 998 characters, but RFC2822 now allows multi-line headers[1], so there's no limit except one that might be imposed by an MTA (and that would generally only be imposed on sending, not receiving.)
1. https://www.ietf.org/rfc/rfc2822.txt https://www.ietf.org/rfc/rfc2822.txt §2.2.3