IETF RUN Working Group Sally Hambridge/Intel
draft-ietf-run-spew-02.txt Albert Lunde/Northwestern University
DON'T SPEW
A Set of Guidelines for Mass Unsolicited
Mailings and Postings (spam*)
Abstract
This document provides explains why mass unsolicited electronic mail
messages are harmful in the Internetworking community. It gives a
set of guidelines for dealing with unsolicited mail for users, for
system administrators, news administrators, and mailing list
managers. It also makes suggestions Internet Service Providers might
follow.
Status of This Memo
This document is an Internet-Draft. Internet-Drafts are working
documents of the Internet Engineering Task Force (IETF), its areas,
and its working groups. Note that other groups may also distribute
working documents as Internet-Drafts. Comments on this draft should
be sent to ietf-run@mailbag.intel.com.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
To learn the current status of any Internet-Draft, please check the
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munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or
ftp.isi.edu (US West Coast).
1. Introduction
The Internet's origins in the Research and Education communities
played an important role in the foundation and formation of Internet
culture. This culture defined rules for network etiquette
(netiquette) and communication based on the Internet's being
relatively off-limits to commercial enterprise.
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As we know, this all changed when U.S. Government was no longer the
primary funding body for the U.S. Internet, when the Internet truly
went global, and when all commercial enterprises were allowed to
obtain Fully Qualified Domain Names. Internet culture had become
deeply embedded in the protocols the network used. Although the
social context has changed, the technical limits of the Internet
protocols still require a person to enforce certain limits on
resource usage for the 'Net to function effectively. Strong
authentication was not built into the News and Mail protocols. The
only thing that is saving the Internet from congestion collapse is
the inclusion of TCP backoff in almost all of the TCP/IP driver code
on the Internet. There was no end-to-end cost accounting and/or cost
recovery. Bandwidth is shared among all traffic without resource
reservation (although this is changing).
Unfortunately for all of us, the culture so carefully nurtured
through the early years of the Internet was not fully transferred to
all those new entities hooking into the bandwidth. Many of those
entities believe they have found a paradise of thousands of potential
customers each of whom is desperate to learn about stunning new
business opportunities. Alternatively, some of the new netizens
believe all people should at least hear about the one true religion
or political party or process. And some of them know that almost no
one wants to hear their message but just can't resist how inexpensive
the net can be to use.
While there may be thousands of folks desperate for any potential
message, mass mailings or Netnews postings are not at all appropriate
on the 'Net. This document explains why mass unsolicited email and
Netnews posting (aka spam) is bad, what to do if you get it, what
webmasters, postmasters, and news admins can do about it, and how an
Internet Service Provider might respond to it.
2. What is Spam*?
The term "spam," as it is used to denote mass unsolicited mailings or
netnews postings, derives from a Monty Python sketch set in a
movie/TV studio cafeteria. During that sketch, the word "spam" takes
over each item offered on the menu until the entire dialogue consists
of nothing but "spam spam spam spam spam spam and spam." This so
closely resembles what happens when mass unsolicited mail and posts
take over mailing lists and netnews groups that the term has been
pushed into common usage in the Internet community.
When unsolicited mail is sent to a mailing list and/or news group it
frequently generates hate mail to the list or group or apparent
sender by people who do not realize the true source of the message.
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If the mailing contains suggestions for removing your name from a
mailing list, 10's to 100's of people will respond to the list with
"remove" messages meant for the originator. So, the original message
(spam) creates more unwanted mail (spam spam spam spam), which
generates more unwanted mail (spam spam spam spam spam spam and
spam). Similar occurrences are perpetrated in newsgroups, but this
is held somewhat in check by "cancelbots" (programs which cancel
postings) triggered by mass posting. Recently, cancelbots have grown
less in favor with those administering News servers since the
cancelbots are now generating the same amount of traffic as spam.
Even News admins are beginning to use filters, demonstrating that
spam spam spam spam spam spam and spam is a monumental problem.
3. Why Mass Mailing is Bad
In the world of paper mail we're all used to receiving unsolicited
circulars, advertisements, and catalogs. Generally we don't object
to this - we look at what we find of interest, and we discard/recycle
the rest. Why should receiving unsolicited email be any different?
The answer is that the cost model is different. In the paper world,
the cost of mailing is borne by the sender. The sender must pay for
the privilege of creating the ad and the cost of mailing it to the
recipient. An average paper commercial mailing in the U.S. ends up
costing about $1.00 per addressee. In the world of electronic
communications, the recipient bears the majority of the cost. Yes,
the sender still has to compose the message and the sender also has
to pay for Internet connectivity. However, the recipient ALSO has to
pay for Internet connectivity and possibly also connect time charges
and for disk space, so for electronic mailings the recipient is
expected to help share the cost of the mailing. Bulk Internet mail
from the U.S. ends up costing the sender only about 1/100th of a cent
per address; or FOUR ORDERS of magnitude LESS!
Of course, this cost model is very popular with those looking for
cheap methods to get their message out. By the same token, it's very
unpopular with people who have to pay for their messages just to find
that their mailbox is full of junk mail. Consider this: if you had
to pay for receiving paper mail would you pay for junk mail?
Frequently spammers indulge in unethical behavior such as using mail
servers which allow mail to be relayed to send huge amounts of
electronic solicitations. Or they forge their headers to make it
look as if the mail originates from a different domain. These kinds
of people don't care that they're intruding into a personal or
business mailbox nor do they care that they are using other people's
resources without compensating them.
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The huge cost difference has other bad effects. Because even a very
cheap paper mailing is going to cost tens of (U.S.) cents there is a
real incentive to send only to those really likely to be interested.
So paper bulk mailers frequently pay a premium to get high quality
mailing lists, carefully prune out bad addresses and pay for services
to update old addresses. Bulk email is so cheap that hardly anyone
sending it bothers to do any of this. As a result, the chance that
the receiver is actually interested in the mail is very, very, very
low.
Doesn't the U.S. Constitution guarantee the ability to say whatever
one likes? First, the U.S. Constitution is law only in the U.S., and
the Internet is global. There are places your mail will reach where
free speech is not a given. Second, the U.S. Constitution does NOT
guarantee one the right to say whatever one likes. The example of
yelling "FIRE" in a crowded theater comes to mind (the Supreme Court
decision which yielded that was from a case where over a hundred
people, mostly children, were trampled to death in the panic that
ensued when people yelled "Fire" in response to a small smoldering
fire in the Iriquois Theatre in Chicago in 1882). In general, the
U.S. Constitution refers to political freedom of speech and not to
commercial freedom of speech. Finally, there are laws which govern
other areas of electronic communication, namely the "junk fax" laws.
Although these have yet to be applied to electronic mail, they are
still an example of the "curbing" of "free speech." Free speech does
not, in general, require other people to spend their money and
resources to deliver or accept your message.
Most responsible Internet citizens have come to regard unsolicited
mail/posts as "theft of service." Since the recipient must pay for
the service and for the most part the mail/posts are advertisements
of unsolicited "stuff" (products, services, information) those
receiving it believe that the practice of making the recipient pay
constitutes theft.
The crux of sending large amounts of unsolicited mail and news is not
a legal issue so much as an ethical one. If you are tempted to send
unsolicited "information" ask yourself these questions: "Whose
resources is this using?" "Did they consent in advance?" "What
would happen if everybody (or a very large number of people) did
this?" "How would I feel if 90% of the mail I received was
advertisements for stuff I didn't want?" "How would I feel if 95% of
the mail I received was advertisements for stuff I didn't want?"
"How would I feel if 99% of the mail I received was advertisements
for stuff I didn't want?"
Although hard numbers on the volume and rate of increase of spam are
not easy to find, seat-of-the-pants estimates from the people on the
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spam mailing list [1] indicate that unsolicited mail/posts seems to
be following the same path of exponential growth as the Internet as a
whole [2]. This is NOT encouraging, as this kind of increase puts a
strain on servers, connections, routers, and the bandwidth of the
Internet as a whole. On a per person basis, unsolicited mail is also
on the increase, and individuals also have to bear the increasing
cost of increasing numbers of unsolicited and unwanted mail. People
interested in hard numbers may want to point their web browsers to
www.junkproof.com where the webmaster there lists the number of spam
messages he has filtered away from his users.
Finally, sending large volumes of unsolicited email or posting
voluminous numbers of Netnews postings is just plain rude. Consider
the following analogy: suppose you discovered a large party going on
in a house on your block. Uninvited, you appear, then join each
group in conversation, force your way in, SHOUT YOUR OPINION (with a
megaphone) of whatever you happen to be thinking about at the time,
drown out all other conversation, then scream "discrimination" when
folks tell you you're being rude. To continue the party
analogy, if instead of forcing your way into each group you stood on
the outskirts a while and listened to the conversation. Then you
gradually began to add comments relevant to the discussion. Then you
began to tell people your opinion of the issues they were discussing,
they would probably be less inclined to look badly on your intrusion.
Note that you are still intruding. And that it would still be
considered rude to offer to sell products or services to the guests
even if the products and services were relevant to the discussion.
You are in the wrong venue and you need to find the right one.
Lots of spammers believe that they can be forgiven their behavior by
beginning their messages with an apology, or by personalizing their
messages with the recipient's real name, or by using a number of
ingratiating techniques. But much like the techniques used by Uriah
Heep in Dicken's _David Copperfield_, these usually have an effect
opposite to the one intended. Poor excuses ("It's not illegal" "This
will be the only message you receive" "This is an ad" "It's easy to
REMOVE yourself from our list") are still excuses. Moreover, they are
likely to make the recipient MORE aggravated rather than less
aggravated.
In particular, there are two very severe problems with
believing that a "remove" feature to stop future mail helps: (1)
Careful tests have been done with sending remove requests for
"virgin" email accounts (that have never been used anywhere else).
In over 80% of the cases, this resulted in a deluge of unsolicited
email, although usually from other sources than the one the remove
was sent to. In other words, if you don't like unsolicited mail, you
should think carefully before using a remove feature because the
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evidence is that they result in more mail not less. (2) Even if they
did work, it would no stop lots of new unsolicited email every day
from new businesses that hadn't mailed before.
4a. ACK! I've Been Spammed - Now What?
It's unpleasant to receive mail which you do not want. It's even
more unpleasant if you're paying for connect time to download it.
And it's really unpleasant to receive mail on topics which you find
offensive. Now that you're good and mad, what's an appropriate
response?
First, you always have the option to delete it and get on with your
life. This is the easiest and safest response. It does not
guarantee you won't get more of the same in the future, but it does
take care of the current problem.
Second, you may consider sending the mail back to the originator
objecting to your being on the mailing-list, but we recommend against
this. First, a lot of spammers disguise who they are and where their
mail comes from by forging the mail headers. Unless you are very
experienced at reading headers discovering the true origin of the
mail will probably prove difficult. Although you can engage your
local support staff to help you with this, they may have much higher
priorities (such as setting up site-wide filters to prevent spam from
entering the site). Second, responding to this email will simply
verify your address as valid and allow them to sell your address to
other spammers. (As was mentioned above in Section 3). Third, even
if the two previous things do not happen, very probably your mail
will be directed to the bit-bucket!
Next, you can carbon copy or forward the questionable mail messages
or news postings to the postmaster of the offending site. You can do
this by sending mail To: Postmaster@offending-site.example. Good
sites are now using an "abuse" address for people to complain about
spam, so you can send complaints about unsolicited mail and posts to
abuse@offending-site.example. Many organizations which send
unsolicited mail have this address aliased to go nowhere, but it
can't hurt to try.
As mentioned above, much spam uses forged headers, and unless you are
experienced at reading the headers it is hard to tell where the mail
was really sent from. Don't assume that the recipient of your wrath
was involved with or supports the spam. If your message is polite,
often they will help you identify the actual perpetrator. Realize
that they are probably getting a large number of complaints, and if
yours is particularly nice, they may be also, but don't be surprised
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if you get a canned response either.
*** IMPORTANT ***
Wherever you send a complaint, be sure to include the full headers
(most mail and news programs don't display the full headers by
default). For mail, it is especially important to show the Received:
headers; for Usenet news, the Path: header. These normally show the
route by which the mail or news was delivered. Without them, it's
impossible to even begin to tell where the message originated.
Everything above regarding complaints to the offending site can be
applied equally to the Service Provider, if you can determine who
their ISP actually is. The is probably the most effective complaint
you can make: If the Service Provider has Terms and Conditions which
have been violated, they can boot the offender from their network.
Much of the success in fighting the spam war has been the result of
very dedicated people complaining to Internet Service Providers about
offenders. At the very least, the ISP who appears to be their
Service Provider, if not actually, is probably running a mail server
without relay blocks, and are thus an open window for spam. Getting
them to close it will help make it that much harder for spammers to
hide.
Your own organization or your local Internet Service Provider may
have the ability to block unwanted mail at their mail relay machines.
If your postmaster wants to know about unsolicited mail, be sure s/he
gets a copy, including headers. You will need to find out the local
policy and comply.
If your personal mailer allows you to write rules, write a rule which
sends mail from the originator of the unwanted mail to the trash.
That way, although you still have to pay to download it, you won't
have to read it!
There is lively and ongoing debate about the validity of changing
one's email address in a Web Browser in order to have Netnews posts
and email look as if it is originating from some spot other than
where it does originate. The reasoning behind this is that web email
address harvesters will not be getting a real address when it
encounters these. There is reason on both sides of this debate: If
you change your address, you will not be as visible to the
harvesters, but if you change your address, real people who need to
contact you will be cut off as well. Also, if you are using the
Internet through an organization such as a company, the company may
have policies about "forging" addresses - even your own! Most people
agree that the consequences of changing your email address on your
browser or even in your mail headers is fairly dangerous and will
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nearly guarantee your mail goes into a black hole unless you are very
sure you know what you are doing. Here there be dragons.
Finally, DO NOT respond by sending back large volumes of unsolicited
mail. Two wrongs do not make a right; do not become your enemy; and
take it easy on the network.
There is a web site called www.abuse.net which allows you to
register, then to send your message to the name of the offending
domain@abuse.net, which will re-mail your message to be best
reporting address for the offending domain. It also contains good
tips for reporting abuse netnews or email messages. It also has some
automated tools you may download to help you filter your messages.
Also check CIAC bulletin I-005 at:
http://ciac/llnl.gov/ciac/bulletins/i-005a.shtml or at
http://spam.abuse.net/spam/tools/mailblock.html.
Check the Appendix for a detailed explanation of tools and
methodology to use when trying to chase down a spammer.
4b. There's a Spam in My Group!
Netnews is also subject to spamming. Here, several factors help to
mitigate against the propagation of spam in news, although they don't
entirely solve the problem. Newsgroups and mailing lists may be
moderated, which means that a moderator approve all mail/posts. If
this is the case, the moderator usually acts as a filter to removed
unwanted and off-topic posts/mail. In Netnews, there are
programs which detect posts which have been sent to multiple groups
or which detect multiple posts >from the same source to one group.
These programs cancel the posts. While these work and keep
unsolicited posts down, they are not 100% effective and spam in
newsgroups seems to be growing at an even faster rate than spam in
mail or on mailing lists. After all, it's much easier to post to a
newsgroup for which there are thousands of readers than it is to find
individual email addresses for all those folks. Hence the
development of the "cancelbots" (sometimes called "cancelmoose") for
Netnews groups. Cancelbots are triggered when one message is sent to
a large number of newsgroups or when many small messages are sent
(from one sender) to the same newsgroup. In general these are tuned
to the "Breidbart Index" [3] which is a somewhat fuzzy measure of the
interactions of the number of posts and number of groups. This is
fuzzy purposefully, so that people will not post a number of messages
just under the index and still "get away with it." And as noted
above, the cancel messages have reached such a volume now that a lot
of News administrators are beginning to write filters rather than
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send cancels. Still, spam gets through, so what can a concerned
netizen do?
If there is a group moderator, make sure s/he knows that off-topic
posts are slipping into the group. If there is no moderator, you
could take the same steps for dealing with news as are recommended
for mail with all the same caveats.
5. Help For Beleaguered Admins
As a system administrator, news administrator, local Postmaster, or
mailing-list administrator, your users will come to you for help in
dealing with unwanted mail and posts. First, find out what your
institution's policy is regarding unwanted/unsolicited mail. It is
possible that it won't do anything for you, but it is also possible
to use it to justify blocking a domain which is sending particularly
offensive mail to your users. If you don't have a clear policy, it
would be really useful to create one. If you are a mailing-list
administrator, make sure your mailing-list charter forbids off-topic
posts. If your internal-only newsgroups are getting spammed from the
outside of your institution, you probably have bigger problems than
just spam.
Make sure that your mail and news transports are configured so that
you don't inadvertently contribute to the spam problem. Ensure your
mail and news transports are configured to reject messages injected
by parties outside your domain. SMTP source routing
<@relay.host:user@dest.host> is becoming deprecated due to its
overwhelming abuse by spammers. You should configure your mail
transport to reject relayed messages (when neither the sender nor the
recipient are within your domain). Your firewall should prohibit
SMTP (mail) and NNTP (news) connections from clients within your
domain to outside servers. Ensure that messages generated within
your domain have proper identity information in the headers, and
users cannot forge headers. Be sure your headers have all the
correct information as stipulated by RFC 822 [4] and RFC 1123 [5].
If you have the capability (are running a mail transfer agent which
allows it) consider blocking well known offending sites from ever
getting mail into your site. Be careful not to block out sites for
which you run MX records! It is a well-known problem that offenders
create domains more quickly than postmasters can block them. Also,
help your users learn enough about their mailers so that they can
write rules to filter their own mail, or provide rules and kill files
for them to use.
There is information about how to "blackhole" netblocks at
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maps.vix.com. There is information about how to configure sendmail
available at www.sendmail.org. Help on these problems is also
available at spam.abuse.net.
Use well-known Internet tools, such as whois and traceroute to find
which ISP is serving your problem site. Notify the postmaster/abuse
address that they have an offender. Be sure to pass on all header
information in your messages to help them with tracking down the
offender. If they have a policy against using their service to post
unsolicited mail they will need more than just your say-so that there
is a problem. Also, the "originating" site may be a victim of the
offender as well. It's not unknown for those sending this kind of
mail to bounce their mail through dial-up accounts, or off
unprotected mail servers at other sites. Use caution in your
approach to those who look like the offender. News spammers
use similar techniques for sending spam to the groups. They have
been known to forge headers and bounce posts off "open" news machines
and remailers to cover their tracks. During the height of the
infamous David Rhodes "Make Money Fast" posts, it was not unheard of
for students to walk away from terminals which were logged in, and
for sneaky folks to then use their accounts to forge posts. Much to
the later embarrassment of both the student and the institution.
One way to lessen problems is to avoid using mail-to URLs, which
allow email addresses to be easily harvested by those institutions
grabbing email addresses off the web. If you need to have an email
address prevalent on a web page, consider using a cgi script to
generate the mailto address.
Participate in mailing lists and news groups which discuss
unsolicited mail/posts and the problems associated with it.
News.admin.net-abuse.announce is probably the most well-known of
these.
6. What's an ISP To Do?
As an ISP, you first and foremost should decide what your stance
against unsolicited mail and posts should be. If you decide not to
tolerate unsolicited mail, write a clear acceptable use policy which
states your position and delineates consequences for abuse. If you
state that you will not tolerate use of your resource for unsolicited
mail/posts, and that the consequence will be loss of service, you
should be able to cancel offending accounts relatively quickly
verifying, of course, that the account really IS being mis-used). If
you have downstreaming arrangements with other providers, you should
make sure they are aware of any policy you set. Likewise, you should
be aware of your upstream providers' policies.
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Consider limiting access for dialup accounts so they cannot be used
by those who spew. Make sure your mail servers aren't open for mail
to be bounced off them (except for legitimate users). Make sure your
mail transfer agents are the most up-to-date version (which pass
security audits) of the software.
Educate your users about how to react to spew and spewers. Make sure
instructions for writing rules for mailers are clear and available.
Support their efforts to deal with unwanted mail at the local level -
taking some of the burden from your sys admins.
Make sure you have an address for abuse complaints. If complainers
can routinely send mail to "abuse@BigISP.example" and you have
someone assigned to read that mail, workflow will be much smoother.
Don't require people complaining about spam to use some unique local
address for complaints. Read and use 'postmaster' and 'abuse'. We
recommend adherence to RFC 2142, _Mailbox Names for Common Services,
Roles and Functions._ [6].
Finally, write your contracts and terms and conditions in such
language that allows you to suspend service for offenders. Make sure
all your customers sign it before their accounts are activated.
Legally, you may be able to stop spammers and spam relayers, but this
is certainly dependent on the jurisdictions involved. Potentially,
the passing of spam via third party computers, especially if the
headers are forged, could be a criminal action depending on the laws
of the particular jurisdiction(s) involved. If your site is being
used as a spam relay, be sure to contact local and national criminal
law enforcement agencies. Site operators may also want to consider
the bringing of civil actions against the spammer for expropriation
of property, in particular the computer time and network bandwidth.
In addition, when a mailing list is involved, there is a potential
intellectual property rights violation.
There are a few law suits in the courts now which claim spammers
interfered with and endangered network connectivity. At least one
company is attempting to charge spammers for the use of its networks
(www.kclink.com/spam/).
7. Security
Certain actions to stop spamming may cause problems to legitimate
users of the net. There is a risk that filters to stop spamming will
unintentionally stop legitimate mail too. Overloading postmasters
with complaints about spamming may cause trouble to the wrong person,
someone who is not responsible for and cannot do anything to avoid
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the spamming activity, or it may cause trouble out of proportion to
the abuse you are complaining about. Be sure to exercise discretion
and good judgment in all these cases.
Lower levels of network security interact with the ability to trace
spam via logs or message headers. Measures to stop various sorts of
DNS and IP spoofing can make this information more reliable.
8. Acknowledgements
Thanks for help from the IETF-RUN working group, and also to all the
spew-fighters. Specific thanks are due to J.D. Falk, whose very
helpful Anti-spam* FAQ proved helpful. Thanks are also due to the
vigilance of Scott Hazen Mueller and Paul Vixie, who run
spam.abuse.net/, the Anti-spam web site. Thanks also to Jacob Palme,
Chip Rosenthal, Karl Auerbach for specific text: Jacob for the
Security Considerations section, Chip for the configuration
suggestions in section 5, Karl for the legal considerations.
9. References
[1] As reported in messages on the spam@zorch.sf.bay.org (private)
mailing list in May, 1997.
[2] Holbrook, J.P., J.K. Reynolds, "Site Security Handbook," RFC
1244, July 1991.
[3] "Current Spam thresholds and guidelines," Lewis, Chris and Tim
Skirvan,
http:www.uiuc.edu/ph/www/tskirvan/spam.html.
[4] Crocker, D., "Standard for the format of ARPA Internet
text messages," RFC 0822, August 1982.
[5] Braden, R.T., "Requirements for Internet hosts - application
and support," RFC 1123, October 1989.
[6] Crocker, D., "Mailbox Names for Common Services, Roles
and Functions," RFC 2142, May 1997.
* Spam is a name of a meat product made by Hormel. "spam" (no
capitalization) is routinely used to describe unsolicited bulk email
and netnews posts.
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10. APPENDIX - How to Track Down Spammers
In a large proportion of spams today, complaining to the postmaster
of the site that is the apparent sender of a message will have little
effect because, either the headers are forged to disguise the source
of the message, or the sender of the message runs their own
system/domain, or both. As a result, it may be necessary to look
carefully at the headers of a message to see what parts are most
reliable, and/or to complain to the second or third-level Internet
providers who provide Internet service to a problem domain.
In many cases, getting reports with full headers from various
recipients of a spam can help locate the source. In extreme cases of
header forgery, only examination of logs on multiple systems can
trace the source or a message.
With only one message in hand, one has to make an educated guess as
to the source. The following are only rough guidelines.
In the case of mail messages, "Received:" headers added by systems
under control of the destination organization are most likely to be
reliable. You can't trust what the source domain calls itself, but
you can usually use the source IP address since that is determined by
the destination domain's server.
In naive mail forgeries, the "Message-ID:" header may show the first
SMTP server to handle the message and/or the "Received:" headers may
all be accurate, but neither can be relied on. Be especially wary
when the Received: headers have other headers intermixed. Normally,
Received: headers are all together in a block, and when split up, one
or the other blocks is probably forged.
In the case of news messages, some part of the Path: header may be a
forgery; only reports from multiple sites can make this clear. In
naive news forgeries, the "NNTP-Posting-Host:" header shows the
actual source, but this can be forged too.
If a spam message advertises an Internet server like a WWW site, that
server must be connected to the network to be usable. Therefore that
address can be traced. It is appropriate to complain to the ISP
hosting a web site advertised in a SPAM. Even if the origin of the
spam seems to be elsewhere. Be aware that the spam could be an
attack on the advertised site also, however -- the perpetrator knows
they'll get deluged with complaints and their reputation will be
damaged. Any spam with an electronic address is it is suspect
because most spammers know they're unwelcome and won't make
themselves so readily accessible.
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Some other "seat-of-the-pants" ways to tell if headers are forged: it
has an X-pmflags: header; it has an X-Advertisement: header; it has a
Comments: header with the string "Authenticated sender is"; it has a
NULL Message=ID: (i.e. <>).
Doing a traceroute on an IP address or DNS address will show what
domains provide IP connectivity from you to that address.
Using whois and nslookup, one can try to determine who is
administratively responsible for a domain.
In simple cases, a user of a responsible site may be exploiting an
account or a weakness in dial-up security; in those cases a complaint
to a single site may be sufficient. However, it may be appropriate
to complaint to more than one domain, especially when it looks like
the spammer runs their own system.
If you look at the traceroute to an address, you will normally see a
series of domains between you and that address, with one or more
wide-area/national Internet Service Providers in the middle and
"smaller" networks/domains on either end. It may be appropriate to
complain to the domains nearer the source, up to and including the
closest wide-area ISP. However, this is a judgement call.
If an intermediate site appears to be a known, responsible domain,
stopping your complaints at this point makes sense.
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Authors' Adresses
Sally Hambridge
Intel Corp, SC11-321
2200 Mission College blvd
Santa Clara, CA 95052
sallyh@ludwig.sc.intel.com
Albert Lunde
Northwestern University
2129 Campus Drive North
Evanston, IL 60208
Albert-Lunde@nwu.edu
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