On 7/17/11 9:18 PM, Always Learning wrote: > >>> Legitimate senders should not use fake, false, misleading credentials. > >> There is no requirement for the greeting name to match any IP, and isn't likely >> to work for multi-homed and/or clustered machines. > > Which type of 'multi-homing' were you thinking about ? > > http://en.wikipedia.org/wiki/Multihoming > > * Single Link, Multiple IP address (Spaces) > * Multiple Interfaces, Single IP address per interface > * Multiple Links, Single IP address (Space) > * Multiple Links, Multiple IP address (Spaces) Multiple interfaces, multiple IP addresses. Sendmail isn't going to track which interface it is sending on and adjust its greeting. > Which type of 'cluster' were you thinking about ? > > http://en.wikipedia.org/wiki/Computer_cluster > > * High-availability (HA) clusters > * Load-balancing clusters > * Compute clusters > > If any of these share the same IP address, they can share the same host > name. There are any number of topologies that use multiple IP addresses for what appears to be one name. A load balancer might be involved, they may or may not accept on the same IP's as they use for outbound connections, they may or may not know the outbound ip. > I am not well acquainted with either of the above two methods, > multi-homed and clusters, but I can not understand why any of them > should resort to using fake identities when sending-out emails. Just because it doesn't match the IP doesn't make it fake. > Can you help me understand why bogus identities are necessary in these > circumstances ? You are the one defining it as bogus. Consider a system where one or more of it's routes to the internet go through nat routers or the nat functionality of a load balancer. The program sending the mail won't even know the IP you see. -- Les Mikesell lesmikesell at gmail.com