EHLO,

While I haven't seen this in the wild, it might be nice to announce our
limits to the world. RFC9422 specifies 3 limits that can be announced:
MAILMAX, RCPTMAX, and RCPTDOMAINMAX. RCPTDOMAINMAX isn't a feature we
support as far as I'm aware, but MAILMAX, and RCPTMAX are implemented,
so why not announce them and save everybody a bit of time where
supported.

OK?

martijn@

diff c2c0b9e23bf5eaddcd93c2360dcbbfbcf852c37e 5e6293dd52780ac700e0b58e520da8dec2411c56
commit - c2c0b9e23bf5eaddcd93c2360dcbbfbcf852c37e
commit + 5e6293dd52780ac700e0b58e520da8dec2411c56
blob - 3dd7af8b5c6aedaf78281af00dbec916ca692db1
blob + a41810eb6dfa5f84883d50d8541b095e2920a54c
--- usr.sbin/smtpd/smtp_session.c
+++ usr.sbin/smtpd/smtp_session.c
@@ -1782,6 +1782,8 @@ smtp_proceed_ehlo(struct smtp_session *s, const char *
 
 	smtp_reply(s, "250-8BITMIME");
 	smtp_reply(s, "250-ENHANCEDSTATUSCODES");
+	smtp_reply(s, "250-LIMITS MAILMAX=%zu RCPTMAX=%zu",
+	    env->sc_session_max_mails, env->sc_session_max_rcpt);
 	smtp_reply(s, "250-SIZE %zu", env->sc_maxsize);
 	if (ADVERTISE_EXT_DSN(s))
 		smtp_reply(s, "250-DSN");