I recently moved out mail operations to a new server. The old server is
running Postfix 2.8 and the new server 2.10.
We had some initial problems with some private blacklists and the new IP
but those were resolved. However, I had a curious problem sending mail
to icloud.com addresses. Postfix was reporting:
lost connection with mx5.icloud.com.akadns.net[17.172.34.68] while
receiving the initial server greeting
to all MX servers for adadns.net.
To get around this initial problem I began relaying outbound mail thru
the old server until the blacklisting was all resolved. However, I am
still unable to send to the adadns.net servers, still getting dropped
connections. They were no help at all resolving the issue.
Finally I tried to send an email by telnet to port 25 at the above IP
from the new server and sure enough the email went through without
issue.
I've looked through the release notes for 2.9 and 2.10 and didn't see
anything related concerning configuration that might explain this.
Any ideas of what I can try next?
postconf -n (irrelevant lines removed/edited):
broken_sasl_auth_clients = yes
command_directory = /usr/local/sbin
config_directory = /usr/local/etc/postfix
daemon_directory = /usr/local/libexec/postfix
data_directory = /var/db/postfix
inet_interfaces = all
local_transport = virtual
mail_owner = postfix
mailq_path = /usr/local/bin/mailq
manpage_directory = /usr/local/man
master_service_disable =
message_size_limit = 50000000
mydestination = $myhostname, localhost.$mydomain, localhost
myhostname = xxx.xxx.xxx
myorigin = $myhostname
newaliases_path = /usr/local/bin/newaliases
queue_directory = /var/spool/postfix
readme_directory = no
sample_directory = /usr/local/etc/postfix
sendmail_path = /usr/local/sbin/sendmail
setgid_group = maildrop
smtp_tls_note_starttls_offer = yes
smtp_use_tls = yes
smtpd_delay_reject = yes
smtpd_helo_required = yes
smtpd_helo_restrictions = permit_mynetworks, reject_non_fqdn_hostname,
reject_invalid_hostname, permit
smtpd_recipient_restrictions = check_recipient_access
hash:/usr/local/etc/postfix/reject_recipients, reject_unauth_pipelining,
reject_non_fqdn_recipient, reject_unknown_recipient_domain,
check_recipient_maps, permit_sasl_authenticated, permit_mynetworks,
reject_unauth_destination, permit
smtpd_sasl_auth_enable = yes
smtpd_sasl_local_domain =
smtpd_sasl_path = smtpd
smtpd_sasl_security_options = noanonymous
smtpd_sender_restrictions = permit_sasl_authenticated,
permit_mynetworks, reject_non_fqdn_sender, reject_unknown_sender_domain,
permit
smtpd_tls_cert_file = /usr/local/etc/postfix/ssl/xxxxx.pem
smtpd_tls_key_file = $smtpd_tls_cert_file
smtpd_tls_loglevel = 1
smtpd_tls_received_header = yes
smtpd_tls_session_cache_timeout = 3600s
smtpd_use_tls = yes
tcp_windowsize = 1400
tls_random_source = dev:/dev/urandom
unknown_local_recipient_reject_code = 550
