Views:
For IPv6 support, make the following changes to in /etc/postfix/main.cf:
default_process_limit=200 
imss_timeout=10m 
imss_connect_timeout=1s 
content_filter = imss:[::1]:10025 
imss_destination_recipient_limit=200 
imss_destination_concurrency_limit=200
For IPv6 support, make the following changes to in /etc/postfix/master.cf:
#IMSS: content filter smtp transport imss for IMSS 
imss unix - - n - - smtp 
  -o disable_dns_lookups=yes 
  -o smtp_connect_timeout=$imss_connect_timeout 
  -o smtp_data_done_timeout=$imss_timeout 
  -o smtpd_tls_security_level=none
#IMSS: content filter loop back smtpd 
[::1]:10026 inet n - n - 200 smtpd 
  -o content_filter= 
  -o smtpd_timeout=$imss_timeout 
  -o local_recipient_maps= 
  -o myhostname=postfix.imss71 
  -o smtpd_client_restrictions= 
  -o smtpd_enforce_tls=no
  -o smtpd_tls_security_level=none
Note
Note
If you copy and paste the preceding configurations, make sure you correct the indentation of all lines accordingly.
In /opt/trend/imss/config/imss.ini, open connection restrictions and point the downstream server IP to IPv6 localhost:
[socket]
proxy_smtp_server_ip=all
[smtp]
smtp_allow_client_ip=127.0.0.1, ::1
downstream_smtp_server_addr=::1