DEFCONF(user_extaddr_fixup, ${sg {$local_part_suffix}{^[-+]}{}})
## Other hosts allowed to relay mail through us.
-DEFCONF(relay_clients, <; +trusted ; 172.31.80.8)
+DEFCONF(relay_clients, <m4_dnl
+; +trusted m4_dnl
+; 172.31.80.8 m4_dnl chiark (VPN)
+; 172.29.198.161 ; 2000:ba8:1d9:a000::1:1 m4_dnl national
+)
## TLS-related settings. We're assuming GNUTLS here, rather than OpenSSL.
## For local connections we are very strict. For random clients, we try