+send_to_server1:
+ driver = smtp
+ allow_localhost
+ hosts = ${if eq {$local_part}{user4} {127.0.0.1} {<; ::1}}
+ port = PORT_D
+ hosts_try_fastopen = :
+ interface = <; ::1 ; HOSTIPV4
+
+send_to_server2:
+ driver = smtp
+ allow_localhost
+ hosts = ${if eq {$local_part}{user4} {127.0.0.1} {<; ::1}}
+ port = PORT_D
+ hosts_try_fastopen = :
+ interface = <; HOSTIPV6 ; HOSTIPV4
+
+send_to_server3:
+ driver = smtp
+ allow_localhost
+ hosts = ${if eq {$local_part}{user4} {127.0.0.1} {<; ::1}}
+ port = PORT_D
+ hosts_try_fastopen = :
+ interface = <; ${if eq{0}{1}{HOSTIPV6}fail}
+
+send_to_server4:
+ driver = smtp
+ allow_localhost
+ hosts = ${if eq {$local_part}{user4} {127.0.0.1} {<; ::1}}
+ port = PORT_D
+ hosts_try_fastopen = :
+ interface = <; ${if eq{0}{1}{HOSTIPV6}{ }}
+
+send_to_server5:
+ driver = smtp
+ allow_localhost
+ hosts = ${if eq {$local_part}{user4} {127.0.0.1} {<; ::1}}
+ port = PORT_D
+ hosts_try_fastopen = :
+ interface = <; ${if
+