Remote Login and Access

A quick reference to the addresses for various servers on the York CS network. Some servers may share the same address but have a different name. This means that name used for that service is a special alias and should be used where possible in case the service moves to another server in the future.

Please note that computers outside of York CS should not use mail.cs.yorku.ca to forward SMTP mail; it will be rejected. Access to POP3 and IMAP is not restricted on mail.cs.yorku.ca.

Rlogin/Rsh The rlogin and rsh protocols are supported within the department only. You may use it to connect to a Unix machine within the department from another machine within the department, but not from a machine outside the department. When accessing the system from a managed Unix machine, you do not need to enter your password when using rlogin or rsh.

SSH Also known as Secure Shell. This is similar to the telnet protocol except that the connection is encrypted. This prevents other people on the network from reading the packets in transit (also known as "sniffing" the packets) and extracting your password. SSH is a good protocol to use when connecting to the departmental machines from a host outside of the department.

By placing lists of remote hosts and remote users in a file called .rhosts in your home directory, you can avoid having to type in your password when connecting from that account on the remote machine. For example, the following entry

somehwere.foobar.com  joe

UNIX machines in York CS are configured to allow rsh and rlogin access from other machines in the their respective network. You do not need to add them to your .rhosts file.

The preferred protocol for connecting to the department from your home ISP or from another remote computer is SSH or Secure Shell. This protocol provides for the encryption of traffic in transit making it very difficult (and in most cases, nigh impossible) for a third party to snoop or listen in.

We operate ssh servers on our time-sharing servers. SSH clients must be used to access the Computer Science time-sharing servers from outside the department. Telnet and rlogin protocols may not be used when connecting to departmental machines from outside the department. Local users (i.e. computers within the department) can still use telnet, rlogin, rsh, and similar protocols.

The Java SSH Applet is provided as a convenience when accessing the department's computers from remote machines which do not have readily available SSH support, but do have a Java-enabled web browser.