Why is the ssh client setuid root?
In conjunction with the previous question, (2.1) OpenSSH needs root authority to be able to bind to low-numbered ports to facilitate rhosts authentication. A privileged port is also required for rhosts-rsa authentication to older SSH releases. Additionally, for both rhosts-rsa authentication (in protocol version 1) and hostbased authentication (in protocol version 2) the ssh client needs to access the private host key in order to authenticate the client machine to the server. OpenSSH versions prior to 3.
