It appears that if I change simple vhost default host (eg. a specific default host for a specific ip range), the server doesn't serve default host if an invalid vhost was attempted to be reached, unless the default host itself has been accessed at least once before, and the original default host is served instead.
Steps to reproduce are, apparently:
a) simple-vhost.server-root = "/srv/www-vhosts/
simple-vhost.default-host = "some.domain.tld"
simple-vhost.document-root = "/"
b) $HTTPremoteip? == "192.168.0.0/16" {
simple-vhost.default-host = "another.tld"
} # the ip range is just sample, obviously
and restart server
c) mkdir -p /srv/www-vhosts/{some.domain.tld,another.tld}
d) from ip within range of 192.168.0.0/16:
echo -ne "GET / HTTP/1.0\r\nHost: nonexistent.tld\r\n\r\n" | netcat the.http.server 80
e) This will serve "some.domain.tld" instead of "another.tld"
f) echo -ne "GET / HTTP/1.0\r\nHost: another.tld\r\n\r\n" | netcat the.http.server 80
g) This will properly serve another.tld
h) Repeat d) and it will properly serve another.tld
