that customer is apparently losing too much mail - last time I checked,
google, aol, yahoo SMTP servers used HELO strings that did not resolve back
Year - i thought there will be many false positive.
what really matters is:
1. the PTR of connecting should be resolvable and the resulting hostname
should resolve back to the IP.
2. the name in HELO/EHLO should be resolvable and should have A/AAAA record
Check ;-)
Does anyone else checks the HELO/ELHO?
very few.
Thanks for feedback!
I will not check HELO.
Kind regards
Philipp
Am 14.09.20 um 15:08 schrieb Matus UHLAR - fantomas:
On 14.09.20 14:35, Philipp Ewald wrote:
we have one customer the reported problems about HELO. We send the RFC821 HELO
for only DOMAIN not FQDN.
The customer scanning the helo and check the PTR and if the PTR don't match the
HELO there is SPAM rating.
this is forbidden by any SMTP RFCs issued so far.
that customer is apparently losing too much mail - last time I checked,
google, aol, yahoo SMTP servers used HELO strings that did not resolve back
to those IPs.
what really matters is:
1. the PTR of connecting should be resolvable and the resulting hostname
should resolve back to the IP.
2. the name in HELO/EHLO should be resolvable and should have A/AAAA record
I don't really like that but we think about to check the HELO too.
Does anyone else checks the HELO/ELHO?
very few.
--
Philipp Ewald
Administrator
DigiOnline GmbH, Probsteigasse 15 - 19, 50670 Köln
Telefon: +49 221 6500-532, Fax: +49 221 6500-690, E-Mail:
philipp.ew...@digionline.de
AG Köln HRB 27711, St.-Nr. 5215 5811 0640
Geschäftsführer: Werner Grafenhain
Informationen zum Datenschutz: www.digionline.de/ds
