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 "1id-abstracts.txt" listing contained in the Internet-Drafts Shadow Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe), 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. Hambridge, Lunde Expires: 19May97 [Page 1] Internet Draft DON'T SPEW November 1997 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. Hambridge, Lunde Expires: 19May97 [Page 2] Internet Draft DON'T SPEW November 1997 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. Hambridge, Lunde Expires: 19May97 [Page 3] Internet Draft DON'T SPEW November 1997 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 Hambridge, Lunde Expires: 19May97 [Page 4] Internet Draft DON'T SPEW November 1997 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 Hambridge, Lunde Expires: 19May97 [Page 5] Internet Draft DON'T SPEW November 1997 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 Hambridge, Lunde Expires: 19May97 [Page 6] Internet Draft DON'T SPEW November 1997 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 Hambridge, Lunde Expires: 19May97 [Page 7] Internet Draft DON'T SPEW November 1997 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 Hambridge, Lunde Expires: 19May97 [Page 8] Internet Draft DON'T SPEW November 1997 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 Hambridge, Lunde Expires: 19May97 [Page 9] Internet Draft DON'T SPEW November 1997 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. Hambridge, Lunde Expires: 19May97 [Page 10] Internet Draft DON'T SPEW November 1997 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 Hambridge, Lunde Expires: 19May97 [Page 11] Internet Draft DON'T SPEW November 1997 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. Hambridge, Lunde Expires: 19May97 [Page 12] Internet Draft DON'T SPEW November 1997 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. Hambridge, Lunde Expires: 19May97 [Page 13] Internet Draft DON'T SPEW November 1997 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. Hambridge, Lunde Expires: 19May97 [Page 14] Internet Draft DON'T SPEW November 1997 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 Hambridge, Lunde Expires: 19May97 [Page 15]