How Pervasive is ISP Outbound Email Filtering?

Erris writes "A member of the Baton Rouge LUG noticed that Cox checks the text of outgoing email and rejects mail containing key phrases. I was aware of forced inbox filtering that has caused problems and been abused by other ISPs in China and in the US. I've also read about forced use of ISP SMTP and outbound throttling, but did not know they outbound filtered as well. How prevalent and justified is this practice? Wouldn't it be better to cut off people with infected computers than to censor the internet?"

Comments

Looking further...

[Spazmania]

Digging further into the Cox situation, the Cox subscriber said:

I tried to send an email. The email only contained text. The text Cox
objected to was "http://my_homebox_IP_number/"

I haven't checked the Cox TOS lately, but don't they prohibit running a home web server like all the other residential internet providers? Hasn't this been the case since for essentially the same length of time that the Internet has been a commercial venture?

Where, exactly, is the story?

[pongo000]

It's not clear to me that Cox actually scanned the message body in its determination that the e-mail in question was spam. There could have been any number of indicators that caused Cox to reject the outbound message.

I also note that Cox's TOS specifically prohibits the hosting of servers:

Servers. You may not operate, or allow others to operate, servers of any type or any other device, equipment, and/or software providing server-like functionality in connection with the Service, unless expressly authorized by Cox.

A more accurate title for this story would be: "User in violation of Cox TOS upset over Cox efforts to enforce TOS."

My advice to said user? Buck up and get business-level service, or find yourself a real hosting service for your mail server.

Kudos to Cox Communications

[merc]

I would like to first state that I am a Cox cable internet subscriber in the Phoenix area. I also happen to wear the abuse desk hat for Arizona's oldest ISPs.

I can say without question that the amount of spam we get from cox is almost NIL. I constantly see spam coming out of Comscat's network, also Verizon and from time to time Time Warner but RARELY Cox. In fact I can't remember the last spam I received that originated from their network.

I don't mind that my egress SMTP port is blocked forcing me to use a MSA (mine is configured to use SMTP AUTH with TLS, which works nicely). The fact is that Cox has their act together in my opinion. The fact that they are a white hat in the abuse category makes me want to continue doing business with them. I don't think what you're seeing here is intentional censorship. It would actually be irresponsible for Cox not to filter outbound mail traffic, since they are bound to have customers that run malware infected / zombied host computers.

Anyway, I say "good job Cox" :)

P.S. I work for an ISP that is NOT Cox--which one might think after reading my glowing statements (in fact we compete against Cox)

ISP != Evil (not necessarily, anyway)

[cbone00]

I own part of a small ISP and CLEC in the South.
We do not use spy on our customers phone calls or throttle their P2P traffic. We are not considering monitoring their Internet traffic for copyrighted (or any other) data.
Maybe some of the big boys are out there using these draconian tactics, but your average, everyday, garden variety, small ISP is just trying to make a living providing a quality alternative to the behemoths out there.
Please don't lump us in with those guys.

All that said... We *do* filter inbound email traffic for viruses and SPAM. We do block inbound port 25 to our dynamic IPs.
We view these actions as our duty to our customers and to the rest of the Internet to do our small part to help at least slow down the rampant propagation of SPAM on the Internet.
We currently block about 95% of the email that hits our domains - and that number is slowly climbing. Do we occasionally throw out the baby with the bath water? Probably so, but it is rare. I can't even remember the last complaint we have gotten about this, so this tells me that our filters are highly effective.
As for blocking port 25, we do this to guard our address space against our own customers being irresponsible with their PC's and not keeping virus software up to date. Getting our address space blacklisted would effect ALL of our customers.

It is not about getting rich. Hardly so. Email is the probably the biggest drain on resources that any ISP faces. If we didn't take these steps, we probably would not be in business.

Everyone wishes we had the less evil Internet of yesteryear back, but it isn't going to happen. The Internet is a cesspool. We have to defend ourselves in the best way we know how.

Re:Not Comcast

[SCHecklerX]

You may have at one point been flagged as being 'infected with a virus'. This is when my comcrap connections always got nuked (I host a mailing list). But instead of filtering just outbound, they would kill everything.

I got tired of fighting with them (and after the headaches they caused with my overpriced business class connection when they took over for the ISP they bought out I was not going to pay for that service again), and discovered DynDNS's mailhop outbound and mailhop relay services. Problem solved. You can have stuff forwarded in on a nonstandard port and sent out that way too.

http://www.dyndns.com/services/mailhop/outbound.html
http://www.dyndns.com/services/mailhop/relay.html