Hi System debian 9 and postfix 3.1.14-0+deb9u1 This is only MX server.
In external server (zabbix) i add a trigger to send e-mail to my MX (1 e-mail per min) and add zabbix (86.xxx.xxx.xxx) to mynetworks in my MX server Al works fine but sometimes i get in log: Apr 16 12:38:21 thebe4 postfix/smtpd[17093]: connect from zabbix-ext.domain.ltd[86.xxx.xxx.xxx] Apr 16 12:38:21 thebe4 postfix/smtpd[17093]: Anonymous TLS connection established from zabbix-ext.domain.ltd[86.xxx.xxx.xxx]: TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits) Apr 16 12:38:21 thebe4 postfix/smtpd[17093]: too many errors after EHLO from zabbix-ext.domain.ltd[86.xxx.xxx.xxx] Apr 16 12:38:21 thebe4 postfix/smtpd[17093]: disconnect from zabbix-ext.domain.ltd[86.xxx.xxx.xxx] ehlo=2 starttls=1 noop=1 commands=4 And I dont have idea postconf |grep "_error_limit" smtpd_hard_error_limit = ${stress?{1}:{20}} smtpd_soft_error_limit = 10 now I add in main.cf debug_peer_list=86.xxx.xxx.xxx and reaload https://paste.debian.net/1140731/ my restryctions in main.cf: ---------- start -------------- mynetworks = 127.0.0.0/8, 86.xxx.xxx.xxx/32 smtpd_helo_required = yes smtpd_helo_restrictions = permit_mynetworks reject_unauth_pipelining, reject_invalid_helo_hostname smtpd_client_restrictions = # ip black / whitlist check_client_access cidr:/etc/postfix/client_checks, --------------------- > 86.xxx.xxx.xxx OK check_client_access cidr:/etc/postfix/amavis_bypass, reject_unauth_pipelining, permit smtpd_sender_restrictions = permit_mynetworks check_sender_access pcre:/etc/postfix/sender_checks.pcre reject_unknown_sender_domain reject_unknown_reverse_client_hostname, reject_non_fqdn_sender reject_unknown_address, reject_unauth_pipelining, permit smtpd_recipient_restrictions = reject_unauth_pipelining, reject_non_fqdn_recipient, reject_unknown_sender_domain, reject_unknown_recipient_domain, permit_mynetworks, permit_sasl_authenticated, # whitlista po stronie serwera check_client_access hash:/etc/postfix/whitelista, reject_unauth_destination, check_recipient_access pcre:/etc/postfix/recipient_checks.pcre, reject_invalid_hostname, reject_unknown_hostname, reject_non_fqdn_hostname #filtry dla testowania mx i spf check_sender_mx_access cidr:/etc/postfix/mx_access.cidr, check_helo_mx_access cidr:/etc/postfix/mx_access.cidr, check_policy_service unix:private/policy-spf, lpolicyd, reject_unlisted_recipient, check_client_access hash:/etc/postfix/rbl_override, reject_rbl_client b.barracudacentral.org, reject_rbl_client dynamic.rbl.tld, reject_rbl_client bl.spamcop.net, reject_rbl_client zen.spamhaus.org, reject_rbl_client cbl.abuseat.org, permit # Data restrictions smtpd_data_restrictions = reject_unauth_pipelining, reject_multi_recipient_bounce, permit #zgodnosc z rfc strict_rfc821_envelopes = yes