View source for SMTP/Port 25 blocked by ISP

{{DISPLAYTITLE:Port 25 blocked by ISP}}
Back when I was living in Japan I switched from Layer 1 from ADSL to FTTP with vDSL and all of a sudden I could no longer connect to port 25 on my server. Despite the fact that the underlying carrier was the same (NTT-East). 

After a while I got fed up with running the old smtp-forward script and did some more research. To my surprise the submission (TCP/587) and smtps (TCP/465) were open as wide as one could hope for. 

A couple of configuration steps in <tt>postfix</tt> and I was up and running without much trouble. Under <tt>/etc/postfix/master.cf</tt> ensure that the line <tt><span class="highlight">submission</span></tt> and <tt><span class="highlight">smtps</span></tt> are not commented. 

 # ==========================================================================
 # service type  private unpriv  chroot  wakeup  maxproc command + args
 #               (yes)   (yes)   (yes)   (never) (100)
 # ==========================================================================
 smtp      inet  n       -       -       -       -       smtpd
 <span class="highlight">submission inet n      -       -       -       -       smtpd
         -o smtpd_etrn_restrictions=reject
         -o smtpd_client_restrictions=permit_sasl_authenticated,reject</span>
 <span class="highlight">smtps    inet  n       -       -       -       -       smtpd
         -o smtpd_tls_wrappermode=yes -o smtpd_sasl_auth_enable=yes</span>
[[Category:Mail]]