On Thu, 21 Dec 2000, Peter Galbavy wrote:
> I cannot find any description of how/what exim does. I will eventually
> look through the code, but an answer from Phil or Nigel or someone
> else who knows canoncially (pun intended - sorry) would help, and if
> the behaviour is (as I hope) to use IP addresses and not names, then
> may I suggest adding this to either the FAQ or the docs ?
Exim checks for "self" by IP address, precisely because checking by name
is error-prone. If the check were purely by name, a rogue hostmaster
could insert, for example,
some.random.domain. MX 0 some.random.host.
some.random.host. A your.ip.address
This would cause your Exim to route some.random.domain to itself. It
doesn't, because it checks the IP address.
I guess this should be documented somewhere, though you are the first
person to ask! (There is a clue in the documentation for
local_interfaces: "Only the IP addresses listed here are taken as the
local host's addresses when routing mail and checking for mail loops.")
Doing this has proved a pain because the functions for determining all
the local addresses vary between OS. IRIX has a completely different
interface, but eventually somebody produced some code for that system.
As well as checking by IP address, there is some checking by name.
hosts_treat_as_local is a list of such names.
--
Philip Hazel University of Cambridge Computing Service,
ph10@??? Cambridge, England. Phone: +44 1223 334714.
