From: "Hallam-Baker, Phillip" <pbaker(_at_)verisign(_dot_)com>
21st Century and the later American BlastFax junk faxes were less
traceable than any spam. With spam you always have the IP address of
the SMTP client and. Unless your fax machine does caller-ID, you have
paid your telephone company for caller-ID, and the junk faxer is not
using any of the several tactics that turn off caller-ID (e.g. a PBX),
you will have no idea from where a junk fax comes.
This is not actually the case. The AID information can be retreived
after the fact. its not like the days of the old Strouger exchanges
where you had to get to the relay before the call ended.
Caller-ID blocking does not stop the AID information and the information
is in the SS7 network in any case. there is no difficulty tracing
back junk faxes, even if they come from a pbx which does not have
an outgoing line number, the fax can be traced to the T1 line by
the SS7 switching ID.
Of course there are ways to trace calls, but in practice they are not
available to the target of a junk fax. The operator of a FAX machine
has no practical way to obtain any idea of the geographical or telephone
network location of the FAX machine that sent a FAX. Even when the
fax header is valid and contains the telephone number of the sending
fax machine, it is impractical for most targets of junk faxes to trace
that number to the source. When I've tried, I've quite understandably
been told by telcos to get a subpoena. Given the $500/$1500 limit on
TCPA fines, that makes even a present and correct telephone number
effectively untraceable.
Of course you can take Vernon's word over the advice of someone who
has done that type of stuff and whose company is in the SS7 switching
business. It is pretty interesting though that every time someone
menti0ons some form of authentication Vernon comes out with a categorical
statement that is completely untrue. Then he repeats it again and again.
Either this is a theological point for Vernon or he is a troll.
What is untrue about my claim that in practice, the operator of a FAX
machine has no practical way to trace a junk fax to the sending machine?
What is inaccurate about my main point that the practical untracability
of junk fax senders's fax machines does not prevent tracing junk faxes
to the responsible party and convincing that party to stop even when
it is nominially overseas?
The relevance of this point is that it shows that email authentication
is not required to trace almost all spam to the responsible party.
Email authentication cannot tell you whether an incoming mail message
from a stranger is spam. This fact is related to the fact that perfect,
unforgable, always present caller-ID bits would not stop junk faxes
and are not necessary to whack junk faxers such as 21st Century and
American BlastFax.
Vernon Schryver vjs(_at_)rhyolite(_dot_)com
_______________________________________________
Asrg mailing list
Asrg(_at_)ietf(_dot_)org
https://www1.ietf.org/mailman/listinfo/asrg