I can confirm that this behavior persists in opensmtpd 7.3.0p2-1, the current sid version.
The package scripts take settings from the (possibly absent) /etc/mailname and /etc/aliases files, and push those into debconf, instead of the other way around. This breaks pre-seeding, and makes the package's debconf support little better than using an editor on those files directly. You can kinda-sorta pre-seed by doing # echo my.mail.name >/etc/mailname # echo "root: my.r...@addr.com" >/etc/aliases and then installing the package, but then you don't get the more elaborate aliases file that is generated by the install scripts. (The configuration scripts are in need of an overhaul, generally. The absence of settings for a smarthost and additional mail-names is conspicuous. Ideally, opensmtpd would have a debconf implementation similar to that of postfix or exim4-config.) --Daniel -- Daniel Richard G. || sk...@iskunk.org My ASCII-art .sig got a bad case of Times New Roman.