Chris wrote:
Hi All
An interesting job was recently advertised on a software coders auction
site.
It goes something like this....
=======================================
Coder wanted to create perl mail program
Mail program operates as an MTA-intermediate
Mail program must be able to forge the previous domain in the MTA chain,
this domain is selectable and will be a valid domain with a reverse DNS
Mail program must be able to switch domains using domain list text file
...
=======================================
From what I can see this "job" specifically targets anti spam measures that
use reverse DNS (ip blacklists) to determine the sender. by simply saying my
name is joe.com and I got message from jane.com for you.
because everybody knows jane.com the message is accepted. (until Jane is
blacklisted through no fault of her own)
...
That is not necessarily true, usually you check the incoming MTA's IP,
not the one further away. This is how open relays get caught, even the
ones claiming to relay mail from Yahoo.
Yakov
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Yakov Shafranovich / asrg <at> shaftek.org
SolidMatrix Technologies, Inc. / research <at> solidmatrix.com
"Power tends to corrupt, and absolute power corrupts absolutely" (Lord
Acton)
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