Whats wrong with open mail relays?
They are insecure. Unwanted and undeliverable spam may swamp any open relay. This will deny you use of the system attacked and of your network, will cause you unproductive work in repair and response to complaints and will bring your organisation and possibly JANET into disrepute. They are unsociable. There is an active anti-spam community seeking to make spam unworkable. One of their most effective activities is the maintenance of public blacklists of systems or networks which are in some sense sources of spam – particularly open relays. Many organisations will refuse mail from listed sources; you will not be able to send or receive mail from their networks and the sanction may extend to other parts of JANET. Of the well-known services, JANET uses the RBL (the MAPS Real-time Blackhole List); the policies and methods of some other lists are more controversial. JANET customer organisations MUST NOT allow any computers on their networks to be misused in this way. Separate documents descr
