- data = ${if exists{${extract{directory}{VDOMAINDATA}{${value}/mail-forward.cdb}}}\
- {${lookup{$local_part}cdb\
- {${extract{directory}{VDOMAINDATA}{${value}/mail-forward.cdb}}}}}}
+ # Manually construct the forwarding address, preserving the
+ # local_part_suffix if the remote host is master.
+ data = ${if and {{exists{${extract{directory}{VDOMAINDATA}{${value}/mail-forward.cdb}}}}\
+ {! eq {${lookup{$local_part}cdb\
+ {${extract{directory}{VDOMAINDATA}{${value}/mail-forward.cdb}}}}}\
+ {}}}\
+ {${local_part:${lookup{$local_part}cdb\
+ {${extract{directory}{VDOMAINDATA}{${value}/mail-forward.cdb}}}}}\
+ ${if eq {${domain:${lookup{$local_part}cdb\
+ {${extract{directory}{VDOMAINDATA}{${value}/mail-forward.cdb}}}}}}{master.debian.org}{$local_part_suffix} {}}\
+ @\
+ ${domain:${lookup{$local_part}cdb\
+ {${extract{directory}{VDOMAINDATA}{${value}/mail-forward.cdb}}}}}}}