ISP Responsibility in Fight Against Spam 314
netpulse writes "Over at CircleID, John Levine shares a letter by Carl Hutzler, AOL Postmaster and Director, blaming irresponsible ISPs as key part of the problem in the long-term fight against spam. Hutzler says: "Spam is a completely solvable problem. And it does not take finding every Richter, Jaynes, Bridger, etc to do it (although it certainly is part of the solution). In fact it does not take email identity technologies either (although these are certainly needed and part of the solution). The solution is getting messaging providers to take responsibility for their lame email systems that they set up without much thought and continue to not care much about when they become overrun by spammers. This is just security and every admin/network operator has to deal with it. We just have a lot of providers not bothering to care.' To which John Levine adds: 'What do we have to do to persuade networks that dealing with their own spam problem, even at significant short term cost, is better for the net and themselves than limping along as we do now?'"
The problem (Score:5, Insightful)
Re:The problem (Score:5, Interesting)
In the end, they'll go somewhere else to spam and we'll lose the revenue.
Re:The problem (Score:5, Insightful)
So it's better for you to profit from the spammer than for someone else to, since someone is going to?
Congratulations, you are part of the problem.
Re:The problem (Score:2, Interesting)
Well I lost one two weeks ago for this very reason. The customer is a prominant business (one of the largest in one of the communities we service, in our area of about 1/4 of a state). They left for Qwest after a year of absolute refusal to address their IT disasters, leading up to the final "last straw" incident in December.
In typical "smaller business with bigger infrastruct
Re:The problem (Score:2, Insightful)
Re:The problem (Score:3, Insightful)
Quite frankly, I think IANNA and the other IP
Re:The problem (Score:2, Insightful)
Usually at this point, someone in management gets an angry ema
Re:The problem (Score:3, Insightful)
Re:The problem (Score:2)
Re:The problem (Score:5, Insightful)
Look, you have your IP block, and it's your damn responsibility to make sure that it isn't being abused.
Actually, the more attention you pay to what your customers' customers are sending over your network, the more legally liable you might be held for anything that slips through. The phone company isn't held responsable if a bank robbery is planned over the phone only because they make no effort to control what is said. (In other words, because they are a common carrier).
As soon as you start controling what your users can put out on the net, you lose common carrier protections.
Keep in mind that the same tactics that help you clamp down on spam will keep you from playing dumb when the Scientologists or others want to SLAPP your customers.
Other things that hinder spam prevention include pointy headed morons who report legitamate mails as spam because they can't be bothered to unsubscribe to double opt-in lists that they DID subscribe to, blackhole lists that carpet bomb large groups of people everytime one unrelated abuser sends a spam (even if that abuser is null routed), or who include sites that somehow offend their political or social values, or might have said something bad about them. There's a reason spamasassin doesn't just take any blackhole list's word for it. Anyone who can't be bothered to check if the From: field is forged before badgering half the world's postmasters, etc.
The last thing we need is to make sure the above foolishness becomes fatal to all but AOL and Earthlink.
Ultimatly, spam will go away when people stop buying things from spammers. Nothing else will likely manage it.
The natural extension to your argument is that automakers are liable for drunk drivers, the phone company is liable for telemarket scams, and of course, the post office is liable for mail fraud.
Re:The problem (Score:2)
There are real risks involved in solving the spam problem with knee-jerk big brother tactics. ISPs fail to be about free exchange of information when common carrier liability exemptions go away, and nothing is w
Corner pay phones don't accept incoming calls. (Score:3, Insightful)
The phone company won't control what you say, but they can do some things like having the corner pay phones only able to make outgoing c
Re:Corner pay phones don't accept incoming calls. (Score:3, Informative)
Can you help us understand why you cant test your email server from remote location when your ISP is blocking OUTBOUND email ( unless you relay it through them ). If you are from linuxlabs I am guessing you know how to use sendmail's "smarterhost", or postfixes "transport" to make your email go through a upstream provider.
Because the email server in question is not on my machine here, it resides on an unrelated network. I would very much like to telnet to it on port 25 and manually step through a trans
Re:The problem (Score:3, Interesting)
No, I don't send out UCE/Spam.
Now, my ISP is not lax about these issues. For example, many of
ISP's over-sell their lines, use that knowledge. (Score:5, Insightful)
Suppose you are an ISP with a single T1.
You don't just sell the available bandwidth. You over-sell it. You might sell 2x your bandwith or 3x or 4x or 5x.
You do that because you know that each of your customers will not be using their entire bandwidth all the time.
But spammers use up a lot more bandwidth than the average customer.You don't do that. You show your boss how that idiot is using 10x the average bandwidth but only paying 1x the average fee.
That should be easy to do.There isn't one government. I get a ton of crap from
The key here is money. The people who behave irresponsibly use more bandwidth than the responsible people (yet pay the same monthly fees).
If you want to clean your own house, that's the way to do it.
That's the carrot. The stick is when your entire block is blacklisted because you did NOT deal with the problem that you knew about.
Re:The problem (Score:4, Informative)
If you answered "yes" to those questions, then a career at Verizon is waiting for you, because that is exactly what they are doing [theregister.co.uk]. If ISPs are going to take responsibility for blocking spam and the prevention of the creation of BotNets that originate most of it then they need to take more care than these idiots.
we block europe and asia... (Score:4, Interesting)
Spamblocking Whole Countries and DSL ISPs (Score:2)
Blocking whole countries by default, without giving the users a choice about it, is rude, stupid, xenophobic, and a good reason for your customers to leave en masse.
On the other hand, *offering* email blockin
Re:Spamblocking Whole Countries and DSL ISPs (Score:2)
Re:Spamblocking Whole Countries and DSL ISPs (Score:3, Informative)
Don't worry, Verizon is working hard to prevent you from doing that! They and BellSouth have petitioned the FCC to allow them to cut off all other ISPs' access to their raw DSL services. They're also making it
Re:The problem (Score:2)
That is true, but one way or the other users will whine.
How about voting laws to send spammers to long-term jail?
Yes, I'm stupid the answer is obvious...PROFIT
Dear every ISP in the world, (Score:5, Funny)
Dear every ISP in the world including the ones in your parent's basement,
Please rid your servers of spammers.
Sincerely,
The Internet
ps Yeah, right.
More Law Suits (Score:3, Insightful)
Re:More Law Suits (Score:2)
Not caring? (Score:4, Interesting)
Re:Not caring? (Score:2)
If they don't know, it's because they don't want to.
He seems to miss.. (Score:3, Informative)
Re:He seems to miss.. (Score:4, Insightful)
The days of "Oh, here's your static IP and full internet access" are bhind us. I'm all for "if you demonstrate clue, you may have unfiltered unbound access; otherwise, no port 25 for you!"
(also: Port 587 is your friend).
Re:He seems to miss.. (Score:5, Informative)
"By default we filter port 25 to only allow outbound email through our mail servers."
You can request to unblock port 25 if you have a static DSL account... an on top of that...
"In addition, we will periodically scan port 25 over your DSL line to make sure your mail server is not an open relay. If we find an open relay on your mail server, the port 25 filter will be reinstated and you will be notified by the contact email address entered above."
If more ISP's were like that.. there wouldn't be as many z0mbi3z...
Re:He seems to miss.. (Score:2)
Re:He seems to miss.. (Score:2)
All in all, one of the most clueful ISPs I've heard of.
Re:He seems to miss.. (Score:2)
"By default we filter port 25 to only allow outbound email through our mail servers."
This means that outgoing port 25 connections are still allowed. All a hacked computer needs to do is be connected to on another port (besides 25) and then send the mail through the DSL providers mail server. This is in effect what is happening.
You probably thought he meant the other way around, but any ISP that blocked outgoing port 25 certainly would be extreme, but
Re:He seems to miss.. (Score:2)
I think that IPV6 and static addresses for everybody will go a long way toward stopping spam.
Breaking the End-To-End model is EVIL (Score:2)
However, there are ISPs with a middle-ground app
Re:He seems to miss.. (Score:2)
1) never heard 'em say yes.
2) on places that allow port 25 (which is free from the start, not "with permission") you still have to deal with the RBL's bitchy little sister, the Dynamic IP Blackhole List.
Re:He seems to miss.. (Score:2, Insightful)
Really?
How do you know this? I'd love to see the stats that support this. I'm not trying to be facetious, I'd really like to get hard data like that.
I agree 100% with Carl. Forcing admins to get a clue about the state of their outbound mail is key. And as he says, there are ways to control all this stuff. Even trojaned PCs can be controlled, by limiting the number of outbound messages from that machine to
5/hour is Too Low, Arbitrary (Score:2)
Re:He seems to miss.. (Score:2)
-russ
Re:He seems to miss.. (Score:2)
*= remember there are a LOT of spmmers people sell kits on how to spam in newspapers etc --;
Blacklisting them publically. (Score:5, Interesting)
Re:Blacklisting them publically. (Score:2, Insightful)
Re:Blacklisting them publically. (Score:2)
I'll kick money into this project. Is there a PayPal page up yet? Has anyone even made a project out of it yet?
a touch of psychology, a brickbat of capitalism (Score:3, Insightful)
How about putting them on an RBL? When their customers can't send emails, and threaten lawsuits for breach of contract, the ISP operators tend to start paying attention.
Re:a touch of psychology, a brickbat of capitalism (Score:2)
Drop their packets. ALL OF THEM. Have the border router use the list, not the mail server.
And before someone yells "collateral damage", I've been on the receiving end of that before (I'm on RoadRunner), so I know damn well the issues.
Re:a touch of psychology, a brickbat of capitalism (Score:2, Insightful)
In my tenure as a network administrator at various locations I've seen the full scope of offenses, from those which are blatant violations of the AUP to those which are users complaining ab
Re:a touch of psychology, a brickbat of capitalism (Score:2)
That works both ways. How about when a customer/employee compains they can't receive any email from some user @domain.com? What happens when it's an extremely important client and they're getting messages "sorry, your address has been rejected from sending mail to this system"? When you're talking about money vs network politics, guess whi
Re:a touch of psychology, a brickbat of capitalism (Score:2)
You can bet that any client or potential client will take note if you complain to them about spam coming from their mail server. If they refuse to take action, making a case for "breach of contract" won't be too difficult.
Besides, if they're really that clueless, how bad do you want to do business with them? Do you really want someone that hazardou
Creds (Score:2, Insightful)
How about "accountability" (Score:2, Interesting)
- don't want your mail servers to be blocked? Secure them so spammers can't use them.
- don't want to be considered a "spamvertising company"? choose a legitimate ad agency.
IMHO a multi-level effort is needed:
- ISP's need to have a blacklist of customers who are known spammers. They need to share info.
- Consumers need to have a website where they can check the legitimacy of a website, and see if it spams to advertise.
- Registrar's need to stop iss
Re:How about "accountability" (Score:2)
That's like putting up a sign saying, "please sue me for libel". It would also probably put you afoul of anti-trust laws.
Accountability - HELP ME GET A FREE MINIMAC (Score:2)
Yeah it is. So, I'm holding you accountable for that lame, unwanted, advertisement in your slashsig. Get a job, or something you can do to make the few hundred it takes to buy a minimac.
How many people have you emailed or bothered with that lame "free stuff" link?
Somebody mod this clown down.
Re:How about "accountability" (Score:2, Insightful)
Re:How about "accountability" (Score:2)
Sigh (Score:3, Interesting)
Clue in to human nature (Score:5, Insightful)
The current email system does not take into account human nature and is therefore broken beyond all hope of an easy solution. It needs to be replaced with a system designed from the ground up with accountability in mind. Period.
responsibility and the expectation thereof (Score:2)
I worked support at Speakeasy Networks for a little while. Speakeasy is well-reputed for letting users do whatever they want with their connection (sans the obviously illegal/unsavo
AOL's spam policy is unreasonable (Score:5, Informative)
Here's how it works: AOL receives N complaints calling something spam after users click on the "mark this as spam" button. So AOL looks at the previous link in the received-from chain and blocks that entire network.
Sounds good right? Wrong.
Say Joe User works at my company part-time from home. Instead of another pop account, he has a forwarding address with our company that forwards to his AOL account. Joe gets spam, and reports it to AOL. AOL looks to see who sent it, sees my company in the "received-from" chain, and blocks not only us, but every other company hosted with our ISP. Thousands of legitimate emails now can't get to AOL addresses.
It gets worse. Many people use the "spam" button like the "delete" key to get rid of stuff they just don't want right now. AOL doesn't educate its users to realize that reporting something as spam has real consequences, and so people mark real email they requested as spam just because it's easier than deleting around it.
Our fabulous domain host FutureQuest [futurequest.net] has had to ban forwarding to AOL addresses as a result. AOL has been completely unreasonable in accepting any responsibility for intelligent spam blocking, and their users and legitimate businesses are suffering.
At least they're trying, but they're far from the good guys here.
That's a problem anywhere. (Score:2)
Joe then reports that email as "spam" to a blacklist.
BAM! You're identified as a spammer.
You see the reject comments on your mail server.
You check the blacklist and look up the emails that were reported.
BAM! Joe is fired.
You show the blacklist site that you're not an open relay or proxy or whatever and you get removed from the blacklist.
If it's coming through YOUR network, it is YOUR responsibility. You can filter spam/viruse
Re:AOL's spam policy is unreasonable (Score:2)
Our fabulous domain host FutureQuest has had to ban forwarding to AOL addresses as a result. AOL has been completely unreasonable in accepting any responsibility for intelligent spam blocking, and their users and legitimate businesses are suffering.
I used to run a virtual webhosting server and had to do the same thing. Customers would have mail to person@legitimatebusiness.com forwarded to same_person@aol.com. Naturally, they would get spam to their business mailbox which would be dutifully forwarded to
Traditional .forward is dead. Get used to it. (Score:2)
See Joe St. Sauver's The Impending End of Traditional .forward-style Forwarding [campus-technology.com]. This is a growing problem, and traditional .forward is dead.
Joe [uoregon.edu] runs network ops for University of Oregon, and has a good set of for-the-public articles at his website.
How the presentation will go (Score:4, Insightful)
Boss: "Thanks for your concern."
Try #2...the CTO...
You: "What do we have to do to persuade networks that dealing with their own spam problem, even at significant short term cost---"
Director: "Cost? My hands are tied...shareholders are disappointed and the board needs convincing anyway."
Try #3...the board...
You: "What do we have to do to persuade networks that dealing with their own spam problem, even at significant short term cost---"
Board: "What is this 'spam' nonsense you're talking about? You know, when I was your age we never had all these technology woes. I don't see how this will benefit anybody. Next on the agenda....."
Only Part of the Problem (Score:2)
Caution (Score:2, Insightful)
Spam is annoying for those who get any but it doesn't justify the hysteria, IMHO.
Spam from home users? (Score:4, Interesting)
(aside: we host a few websites, one of which we discovered was running an exploitable version of PHPNuke - but not before a spammer did and pumped ~20,000 emails into our queue. I noticed it pretty quickly and deleted them and blocked this webmail software across all these sites lest it happen again - but it was an interesting demonstration to me that spammers look for any and every leverage they can get. I keep a much closer eye on our mail queue statistics now!)
Re:Spam from home users? (Score:3, Interesting)
I've seen known compromised machines spewing for over a month after abuse@ was notified, so it's still an ISP issue.
Re:Spam from home users? (Score:2)
Re:Spam from home users? (Score:2)
too low... (Score:2)
Sasktel, I love you! (Score:3, Informative)
My ISP, Sasktel [sasktel.com] in Saskatchewan, Canada has recently implemented a spam filtering service that has so far resulted in 2 false positives and no delivered spam. It completely blocks all virused emails as well. Finally, it sends out an email every once in a while to remind me to check the status of spam at the online message centre, where you can look at all email sent to me that is "suspicious."
They also have a fairly comprehensive policy against hosting spammers, which is nice to hear. I know that many of my friends who use other ISPs have been recently flooded with spam, but I've not had any problems thus far. It's nice to have an ISP that cares about its customers!
Re:Sasktel, I love you! (Score:2)
p.s. if it's that great, how come you don't show your email address publicly on Slashdot? :-)
If they make enough money spamming... (Score:4, Interesting)
Re:If they make enough money spamming... (Score:3, Interesting)
Re:If they make enough money spamming... (Score:3, Informative)
#1. They hide behind real isps cidrs, meaning we'd have to block that isps ip range to stop them, and most of the time they have legit users and this is bad.
#2. Their ability to pick up and move about. They can move as soon as they are blocked, and are constantly pulling up roots and moving to the next provider that they can suck on for the next
A nation of zombies. (Score:3, Interesting)
If you own your own ISP, you're limited to the bandwidth that you're paying for (and you can be blocked easily).
With a bunch of zombie machines, you have TONS more bandwidth and you're not paying for it!
Plus - all those processors sending spam.
Just 10 zombies on 256K upload cable modems is 2.5Mb.
A regular T1 is only 1.54Mb.
Re:If they make enough money spamming... (Score:2)
They are.
Top five spammers based on spams-per-ip to hit my spam traps this year;
#1 1.73413 AS25957 (ACETE-1 Acetech USA, Inc)
#2 0.89844 AS24734 (ASN-TECHMEX Techmex SA Autonomous System)
#3 0.38965 AS33012 (EMC-67 Expedite Marketing Corporation)
#4 0.15137 AS11677 (ITESM Rectoria Universidad Virtual)
#5 0.11523 AS34061 (GEDOMAX-AS SC Gedomax Pro 2003 SRL)
"ISP" fronts for Spammers - Moving Target (Score:3, Interesting)
Evidence? (Score:2)
Supporting (or contradictory) data is in short supply.
The article mentions AOL has "all but solved" their spam problem, but doesn't give any real numbers.
ISPs need to do more to stop spam zombies (Score:2)
ISPs should all be running good email virus scanners to remove viruses and infected attachments (including spam and DDOS zombie bots)
They should be blocking ports used by these zombies (i.e. things like MSRPC, windows file sharing etc and also ports used to send control messages to the trojans)
They should be educating users about how not to get infected with trojans.
And t
Re:ISPs need to do more to stop spam zombies (Score:3, Interesting)
When his honey pot receives mail it tracks down the mail to the sending machine, works back to the ISP and mails a report to the ISP admins in realtime. If the PC is own3d then the admins usually disconnect it from the net fairly soon until the owners have fixed it, so the machines can only be used for a short time.
Because the admins wo
Gonna have to come from the top down... (Score:2, Interesting)
I used to be completely against ISPs blocking port 25 from non-MX machines to the outside world. Unfortunately, I've had to change my opinion. The vast majority of the spam that ends up in my spam mailbox (t
irresponsible ISPs (Score:2)
others have retarded / broken "content filters" making it impossible to report to them any abusive emails originating directly from their customers.
just a few of the 500+ irresponsible networks i track, who orig
Spam is a worldwide problem... (Score:2)
100% compliance is NOT a solution (Score:2)
Any solution to spam (or, for that matter, any annoyance in life) which relies on 100% cooperation is doomed to fail. The successful solution will be one that allows a customer to stop receiving spam entirely regardless of what everyone else does.
One Hardline Solution (Score:2)
I initially found this pretty restrictive (eg: I wanted to run my own mail server, quite in violation of their TOS) however now I have my mail server running on another ISP. I can send directly throu
Just a thought (Score:2, Interesting)
Re:Just a thought (Score:2, Interesting)
It's the same with mail servers, fix one problem and another appears, ad infinitum. Bottom line; SMTP is useless and should be relegated to the dark ages when only scientists and soldiers used email.
SMTP requir
oh really ? Have you tried to call AOL lately? (Score:3, Interesting)
here's a post i made in my blog about a situation that arived because of AOL's "system". Ever since that episode, i haven't been impressed at all by these people.
--------(start idiotic message from AOL)----------
Date: Mon, 5 Apr 2004 09:04:13 -0400 (EDT)
From: postmaster@aol.com
Subject: AOL email concerns for isp-where-i-work-abuse.net
To: abuse@isp-where-i-work-abuse.net
X-Scanned-By: MIMEDefang 2.39
Dear isp-where-i-work-abuse.net,
You are receiving this message via our automated "Report Card" process (which helps analyze AOL's Internet inbound mail) because our available data indicate that isp-where-i-work-abuse has risen above the acceptable threshold for complaints:
Total number of AOL member complaints: 186
AOL takes proactive steps to contact owners of mail servers whose e-mail transmissions are impairing the functioning of AOL's proprietary e-mail system, or causing significant levels of AOL customer complaints.
AOL requests that you take immediate steps to resolve the issues identified in this AOL Report Card. In the absence of a satisfactory resolution, AOL reserves the right to take measures to protect its email network and its member goodwill from any possible damage. These measures may include declining to accept e-mail transmissions from isp-where-i-work-abuse.net through AOL's proprietary e-mail network.
AOL strives to provide the best online experience possible for our members, and we pride ourselves on being intensely focused on consumers and their needs. Email is a core feature of the AOL service, and the proper functioning of AOL's e-mail system is vital to our members' goodwill.
Please review AOL's e-mail policies and guidelines, as well as other technical details concerning e-mail on the AOL network, at http://postmaster.info.aol.com
------------(end message)--------------
Ooohhh, AOL's proprietary e-mail network. No information that is gonna be any use in determining WHY people are complaining at all. I guess this should not be a surprise, considering this crap is coming in from AOL! So i do the next available thing , i go to the website. Result : No information that is gonna be any use in determining WHY people are complaining at all. But there's a phone number.
Result of calling 1-888-212-5537:
*dials phone*
"The holding time for the next available consultant will be more than ten minutes."
"Thank you for calling America online
*spits water all over desk, workdesk and papers*
(musak)
(an hour later)
Hello, this is postmaster helpdesk, can i help you?
REP:"oh, that's because you don't currently have a feedback loop with us."
ME : "huh? but we received your report cards in the abusemail box."
REP:"Yes, but you don't have a feedback loop with us"
ME
REP:"Yes, but we made our own database"
ME
REP:"I cannot comment on that"
REP: So what are your mail server's IP adresses.
ME : We have several : we're an ISP.
REP: Alright, then give em to me.
ME : That's why we use DNS names for our mail servers : if one breaks, we change the IP to another server while we fix the previous one.
REP: So you can't give me the IPs?
I don't see what all the fuss is about (Score:2)
Spews (Score:2)
Spews [spews.org] -- love it or hate it -- is all about making hosting spammers more expensive to ISPs.
Personally, I find that as a side effect it it an incredible tool for moving spam from my inbox to my junk mail folder.
a serious problem (Score:2, Insightful)
Re:Block port 25 outbound? (Score:5, Insightful)
Because their userbase is:
A) Enormous; and
B) Very, very stupid.
What does this mean?
Look, my ISP -- whose co-owners I've got on speed-dial, and is incredibly clueful -- doesn't have a user spam problem, because pretty much only geeks use them (we pay a bunch extra for the privilege, too). AOL, on the other hand, has the saddest, most pathetic users in the world -- people who are the prime target for PC-p0wning software. Add to that the fact AOL is, like, pretty much the easiest ISP to sign up for. In other words, they're the biggest, fattest, juiciest spam target out there.
And yet, having looked at the 23,507 spam messages I've gotten over the last 303 days, do you know how many came from AOL?
Zero.
I know Carl (not personally, but I'm on some mailing lists with him). He's pretty damn smart. He has to be. Same thing about the rest of the anti-abuse folks at AOL. They're smart, and they're dedicated, and they're very, very, very good.
Re:Block port 25 outbound? (Score:2)
Re:Block port 25 outbound? (Score:2)
AOL's marketing and UI are fine for their customer base. But extremely limited and really only suitable for beginners. Like MS-Win*.
I fear an expansion of their 80/20 mentality will shut the 'net down for the minority. And with it, much of what has made the 'net interesting. Freedom matters, and there's a price to be paid in disorderliness.
Re:Block port 25 outbound? (Score:2)
Where the hell was Carl from 1995 - 2000 when AOL was developing it's mighty subscriber base along with it's unindoctrinated users who were one of the main sources of spam to begin with?
Now, the biggest ISP can dictate if my users can send their users e-mail? This is because the owner of my block didn't set up reverses for it's range and won't do so any time soon.
At a minimum, they should respond to removal requests from respons
Re:The problem is (Score:2)
Re:AOL doesn't check complaints before banning (Score:5, Informative)
At any rate, once we cleaned up the problem, I emailed AOL and let them know we'd dealt with it and all was good.
If you want to talk about an ISP that was tough to deal with, it's RoadRunner. Somehow we got on their block list. They wouldn't respond to my emails to their abuse address, just a standard email with instructions. Even managed to get someone down in Florida who knew a friend of a friend of mine to call and complain, the technician got me a phone number to their security center in Virginia (or wherever it was), and all I got was a recorded message to email them, and then it hung up without even giving me a chance to leave a message.
I eventually gave up, blocked all RoadRunner addresses going in. Six months later I checked, and we were off the blacklist.
Re:Blacklists could be the answer (Score:2)
(This is of course assuming you meant upstream bandwidth providers.)
IRL, blacklists operate by checking to see if the incoming smtp server is on a blacklist, and 90% of the time (pulled that out of my ass), this will be on the downstream providers caching server (if they are smart enough to have one).
Re:I find blocking ports 1-65535 TCP/UDP in/out (Score:2)
Re:but what about the users? (Score:2)
you give them a web-based control panel that lets them control filtering for their account.
we find most customers choose to turn filtering ON rather than turn it OFF.
Raise the rates, and then give a "discount". (Score:2)
"Hi! Thanks for calling Big-Internet-Service. This month we're having a special of $5 off our monthly bill with "secured service". This service will help make sure your email to your friends gets to them by making sure your machine doesn't end up on a blacklist somewhere. Would you like the $5 discount?"
"What's the alternative?"
"You pay us $5 extra a month and we cut your connection