Hello,
I noticed that for most emails I submit through my instance of OpenSMTP,
there are most of the time (but interestingly not always) two envelopes
in the queue. However, mail delivery works fine, and only one copy
arrives at the recipient.
To illustrate the case, sending a mail (sensitive info replaced),
results in the queue to be before relay:
# smtpctl show
10da45aca8ae47a5|inet4|mta|auth|sen...@snd.com|recei...@rcv.com|recei...@rcv.com|1580120435|1580120435|1580120436|0|inflight|2|
10da45acc22f61bd|inet4|mta|auth|sen...@snd.com|recei...@rcv.com|recei...@rcv.com|1580120435|1580120435|1580120436|0|inflight|2|
More info on both envelopes:
# smtpctl show envelope 10da45aca8ae47a5
version: 3
dispatcher: relay
tag: MSA
type: mta
smtpname: mx.ownmailserver.com
helo: localhost
hostname: <client_hostname>
sockaddr: <client_IP>
sender: sen...@snd.com
rcpt: recei...@rcv.com
dest: recei...@rcv.com
ctime: 1580120435
last-try: 0
last-bounce: 0
ttl: 0
retry: 0
flags: authenticated
dsn-notify: 0
# smtpctl show envelope 10da45acc22f61bd
version: 3
dispatcher: relay
tag: MSA
type: mta
smtpname: mx.ownmailserver.com
helo: localhost
hostname: <client_hostname>
sockaddr: <client_IP>
sender: sen...@snd.com
rcpt: recei...@rcv.com
dest: recei...@rcv.com
ctime: 1580120435
last-try: 0
last-bounce: 0
ttl: 0
retry: 0
flags: authenticated
dsn-notify: 0
Looks like they are exact duplicates, but with their distinct envelope
IDs. Here's the relay log:
Jan 27 10:20:43 schacht01 smtpd[50381]: 11490b9d19a2b420 mta delivery evpid=10da45aca8ae47a5 from=<sen...@snd.com> to=<recei...@rcv.com>
rcpt=<-> source="<mail_server_addr>" relay="<recv_mx_addr>" delay=8s result="Ok" stat="250 2.6.0
<2020015810049931962...@snd.com> [InternalId=3259974] Queued mail for delivery"
Jan 27 10:20:43 schacht01 smtpd[50381]: 11490b9d19a2b420 mta delivery evpid=10da45acc22f61bd from=<sen...@snd.com> to=<recei...@rcv.com>
rcpt=<-> source="<mail_server_addr>" relay="<recv_mx_addr>" delay=8s result="Ok" stat="250 2.6.0
<2020015810049931962...@snd.com> [InternalId=3259974] Queued mail for delivery"
So, both are relayed, it seems, however, on the receiving side only one
copy arrives, and no errors reported. I guess that if there is a double
relay, the receiver might still only accept one copy, b/c the Message-Id
being the same? Or isn't there a double relay to begin with?
I'm also a bit puzzled why in rare cases, only one envelope is in the
queue - what I would expect - but I cannot find why or what the
difference is.
I have only one thing listening on the submission port:
# netstat -4an | grep -F .587
tcp4 0 0 <mail_server_addr>.587 *.* LISTEN
The corresponding smtp.conf's config file line is, as well as the used
action/match pair:
listen on $listen_ext port submission tls-require pki mx_pki auth hostname $mx_domain senders
<sender_map> mask-src tag "MSA"
action "relay" relay helo $mx_domain
match auth from any for any action "relay"
So I guess my question is very simple in nature: Is this normal
behaviour, or is there something going on that needs to be investigated?
Thank you
