I don't think it's likely wildcards will ever be implemented in /etc/hosts, but you could hack glibc to support it without too much effort I think (somewhere in

I don't think it's likely wildcards will ever be implemented in /etc/hosts, but you could hack glibc to support it without too much effort I think (somewhere in this file https://sourceware.org/git/?p=glibc.git;a=blob;f=nss/nss_files/files-hosts.c;h=6db2535159e03f286c0cb968913fbad2d0809408;hb=72c90ed01fb5ba17bbcfbe0a67ec044f4b868618 https://sourceware.org/git/?p=glibc.git;a=blob;f=nss/nss_fil...) (It's possible that you'll sometimes run into applications that do their own /etc/host parsing.)