In some situations, it makes sense to have the repository in use by ikiwiki reside on a different machine. In that case, one could juggle SSH keys for the post-update hook. A better way may be to provide a different do parameter handler for the CGI, which would pull new commits to the working clone and refresh the wiki. Then, the remote post-update hook could just wget that URL. To prevent simple DoS attacks, one might assign a simple password.