Ciao!How are you?Problem:I need 2 interfaces, because the fast ISP blocks 25 port, the slower is open.  I can telnet with the required interface:   telnet -b 192.168.81.20 alt2.gmail-smtp-in.l.google.com 25  Trying 74.125.68.27...Connected to alt2.gmail-smtp-in.l.google.com.Escape character is '^]'.220 mx.google.com ESMTP q14si1562820plk.485 - gsmtpThe wrong is not working telnet -b 192.168.78.20 alt2.gmail-smtp-in.l.google.com 25 Trying 74.125.68.27...telnet: Unable to connect to remote host: Connection refusedroot@server:/etc/postfix# I got the right settings (smtp_bind_address, the one I need and works with telnet):smtp      inet  n       -       y       -       -       smtpd  -o content_filter=spamassassin  -o smtp_bind_address=192.168.81.1submission inet n       -       y       -       -       smtpd  -o syslog_name=postfix/submission  -o smtpd_tls_security_level=encrypt  -o smtpd_sasl_auth_enable=yes  -o smtpd_client_restrictions=permit_sasl_authenticated,reject  -o smtp_bind_address=192.168.81.1smtps     inet  n       -       y       -       -       smtpd  -o syslog_name=postfix/smtps  -o smtpd_tls_wrappermode=yes  -o smtpd_sasl_auth_enable=yes  -o smtpd_client_restrictions=permit_sasl_authenticated,reject  -o smtp_bind_address=192.168.81.1Still, I get this error:Jun 07 13:19:04 server postfix/smtp[10823]: connect to alt1.gmail-smtp-in.l.google.com[108.177.14.27]:25: Connection refusedJun 07 13:19:04 server postfix/smtp[10823]: connect to alt1.gmail-smtp-in.l.google.com[2a00:1450:4010:c0f::1b]:25: Network is unreachableJun 07 13:19:05 server postfix/smtp[10823]: connect to alt2.gmail-smtp-in.l.google.com[74.125.68.27]:25: Connection refusedJun 07 13:19:05 server postfix/smtp[10823]: C625334017A: to=<alabard@gmail.com>, relay=none, delay=12983, delays=12976/0.01/7.4/0, dsn=4.4.1, status=deferred (connect to alt2.gmail-smtp-in.l.google.com[74.125.68.27]:25: Connection refused)The settings are correct, why I get connection refused?If you know, thanks so much!Ciao!  More:Routing:Kernel IP routing tableDestination     Gateway         Genmask         Flags Metric Ref    Use Iface0.0.0.0         192.168.78.1    0.0.0.0         UG    10     0        0 enp2s00.0.0.0         192.168.81.1    0.0.0.0         UG    30     0        0 enp1s0192.168.78.0    0.0.0.0         255.255.255.0   U     0      0        0 enp2s0192.168.81.0    0.0.0.0         255.255.255.0   U     0      0        0 enp1s0Ifconfig:enp1s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500        inet 192.168.81.20  netmask 255.255.255.0  broadcast 192.168.81.255        inet6 fe80::9ade:d0ff:fe04:23c3  prefixlen 64  scopeid 0x20<link>        ether 98:de:d0:04:23:c3  txqueuelen 1000  (Ethernet)        RX packets 265  bytes 49826 (48.6 KiB)        RX errors 0  dropped 0  overruns 0  frame 0        TX packets 104  bytes 25251 (24.6 KiB)        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0enp2s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500        inet 192.168.78.20  netmask 255.255.255.0  broadcast 192.168.78.255        inet6 fe80::eeaa:a0ff:fe1b:4d84  prefixlen 64  scopeid 0x20<link>        ether ec:aa:a0:1b:4d:84  txqueuelen 1000  (Ethernet)        RX packets 4733  bytes 850839 (830.8 KiB)        RX errors 0  dropped 0  overruns 0  frame 0        TX packets 4911  bytes 934827 (912.9 KiB)        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536        inet 127.0.0.1  netmask 255.0.0.0        inet6 ::1  prefixlen 128  scopeid 0x10<host>        loop  txqueuelen 1  (Local Loopback)        RX packets 8049  bytes 3219724 (3.0 MiB)        RX errors 0  dropped 0  overruns 0  frame 0        TX packets 8049  bytes 3219724 (3.0 MiB)        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0my.conf# Debian specific:  Specifying a file name will cause the first# line of that file to be used as the name.  The Debian default# is /etc/mailname.#myorigin = /etc/mailnamesmtpd_banner = ESMTP mail.patrikx3.tkbiff = no# appending .domain is the MUA's job.append_dot_mydomain = no# Uncomment the next line to generate delayed mail warnings#delay_warning_time = 4hreadme_directory = no# See http://www.postfix.org/COMPATIBILITY_README.html -- default to 2 on# fresh installs.compatibility_level = 2# TLS parameters#smtpd_tls_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem#smtpd_tls_key_file=/etc/ssl/private/ssl-cert-snakeoil.key#smtpd_use_tls=yes#smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache#smtp_tls_session_cache_database = btree:${data_directory}/smtp_scachesmtpd_tls_cert_file= /etc/ssl/acme/patrikx3.tk/fullchain.cersmtpd_tls_key_file=/etc/ssl/acme/patrikx3.tk/patrikx3.tk.keysmtpd_use_tls=yessmtpd_tls_auth_only = yessmtpd_sasl_type = dovecotsmtpd_sasl_path = private/authsmtpd_sasl_auth_enable = yessmtpd_recipient_restrictions = permit_sasl_authenticated, permit_mynetworks, reject_unauth_destination, check_policy_service unix:private/policyd-spf# See /usr/share/doc/postfix/TLS_README.gz in the postfix-doc package for# information on enabling SSL in the smtp client.#smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destinationmyhostname = mail.patrikx3.tkalias_maps = hash:/etc/aliasesalias_database = hash:/etc/aliasesmyorigin = /etc/mailnamemydestination = localhostrelayhost = mynetworks = 127.0.0.0/8# 5 gigabytmailbox_size_limit = 5368709120# 50 megabytemessage_size_limit = 52428800recipient_delimiter = +inet_interfaces = allinet_protocols = allvirtual_transport = lmtp:unix:private/dovecot-lmtpvirtual_mailbox_domains = mysql:/etc/postfix/mysql-virtual-mailbox-domains.cfvirtual_mailbox_maps = mysql:/etc/postfix/mysql-virtual-mailbox-maps.cfvirtual_alias_maps = mysql:/etc/postfix/mysql-virtual-alias-maps.cf# spfpolicyd-spf_time_limit = 3600#opendkimsmtpd_milters = inet:127.0.0.1:8891non_smtpd_milters = $smtpd_miltersmilter_default_action = acceptmilter_protocol = 2The required interface has route as well:iface enp1s0 inet dhcp         metric 30         post-up ip route add 192.168.81.0/24 dev enp1s0 src 192.168.81.20 table rt2         post-up ip route add default via 192.168.81.1 dev enp1s0 table rt2         post-up ip rule add from 192.168.81.20/32 table rt2         post-up ip rule add to 192.168.81.20/32 table rt2
postfix dual interfaces, isp1 port 25 blocked, fast, isp2 port open, but slow
linux;postfix;smtp