Updating old CentOS 4 DNS servers to CentOS 5, one of our zones has a number of entries with underscores in.  Starting named results in the following error and named refusing to start.

masters/example.com.db:33: mail_server.example.com: bad owner name (check-names)

I've tried including

check-names master ignore;

in the options but this isn't making any difference.  I've read a lot of debate on whether underscores should be allowed, but for the time being we're stuck with these entries so I need to get this working.

Any thoughts?

Thanks, jc