Internet and e-mail policy and practice
including Notes on Internet E-mail
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31 Mar 2012
I opined about a year ago that DNS blacklists wouldn't work for
mail that runs over IPv6 rather than IPv4.
The reason is that IPv6 has such a huge range of addresses that spammers can easily send
every message from a unique IP address, which means that recipient systems will fire
off a unique set of DNSBL queries for every message, which will swamp DNS caches, since
they won't be able to reuse cached results from previous queries like they can for
Now I'm much less sure this will be a problem, because it's not clear that DNSBL
results benefit from caches now.
See more ...
Trackback link is https://jl.ly/Email/v6blre.trackback
05 Mar 2012
Courtesy forwards have been a standard feature of e-mail systems about
as long as there have been e-mail systems. A user moves or changes jobs
or something, and rather than just closing the account, the mail system
forwards all the mail to the user's new address. Or a user with multiple
addresses forwards them all to one place to be able to read all the
mail together. Since forwarding is very
cheap, it's quite common for forwards to persist for many years.
Unfortunately, forwarding is yet another thing that spam has screwed
up. If you just forward all the mail that arrives at a typical address,
most of what you'll be forwarding is spam.
From the point of view of the system you're forwarding to, you're the one
sending the spam, and they're likely to block you.
Fortuately, there are some ways to mitigate the damage.
See more ...
Trackback link is https://jl.ly/Email/forward.trackback
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