Comments please on configuration and filters to protect an e-mail address

[skolnick]

I have two e-mail addresses on another system that I want to completely protect from distribution. I'd like to use another address as the "external face" of the protected ones.

Context: I have limited connectivity over shortwave radio while I am at sea. E-mail connectivity is extremely slow: 30 - 100 bps (yes bits) depending on propagation conditions and connect time is limited by the terms of the service agreements. There is limited spam filtering. Once an e-mail address is harvested by the spammers I could easily use all my connect time on spam, burying my real mail in the morass.

My experience crossing the Atlantic last year made it very clear that instructions to friends and family not to post or disseminate the addresses I was using is not a sufficiently reliable protection. <grin>

My idea is to use a FQ address to protect the radio addresses.

Incoming mail is easy: set up 'boatatsea@domain.com' using a whitelist to allow forwarding to a radio address and forwarding everything else to my usual address for normal spam processing and to read when I next have real Internet connectivity.

Outgoing mail is harder. I don't want the radio addresses exposed anywhere, including in e-mail headers. The only thing I can think of is to send outgoing mail to a FQ address with a fixed format in the body (first three lines are to: cc: and bcc: ) and use a custom filter processor to rewrite the message headers with those addressees and rewrite the sender information as 'boatatsea@domain.com'. The solution doesn't have to be elegant (no one will use the outgoing part except for me), but it should be simple.

I know that ordinarily rewriting headers is not considered good practice, but I am looking at this as part of the original message generation and sending process.

Comments on this approach, or ideas for something better, would be greatly appreciated.

For general interest, here is a link to a picture of my boat: S/V Auspicious (http://www.skolnick.org/images/rc/Auspicious2.jpg)

[hobbes]

Nice boat Dave. How about setting up a form (password protected?) on your site where friends & relatives can email you? The address would never need to be exposed, and if you make it long/unique enough, you should be able to avoid random spams.

-- ah, the good old shortwave days! Before hobbes, I was known as PY1-YAU --

[skolnick]

How about setting up a form (password protected?) on your site where friends & relatives can email you? The address would never need to be exposed, and if you make it long/unique enough, you should be able to avoid random spams.
Could do that, except for the friends who are "out there" similarly without Internet access. Big surprise that long distance sailors have other long distance sailors as friends? <grin>

-- ah, the good old shortwave days! Before hobbes, I was known as PY1-YAU --
Neat! How long were you in Brazil? The e-mail technology has gotten pretty sophisticated. There are some people doing IP over HF! I use Winlink (PACTOR over ham radio frequencies) and Sailmail (PACTOR over marine HF radio frequencies) which are the most used mechanisms for interfaces with Internet e-mail.

PY1YAU de KO4MI 73 SK

[hobbes]

Could do that, except for the friends who are "out there" similarly without Internet access. Big surprise that long distance sailors have other long distance sailors as friends? <grin> Yeah, but those friends will know better:)

Neat! How long were you in Brazil? The e-mail technology has gotten pretty sophisticated. There are some people doing IP over HF! I use Winlink (PACTOR over ham radio frequencies) and Sailmail (PACTOR over marine HF radio frequencies) which are the most used mechanisms for interfaces with Internet e-mail. Born & bred, though left a long time ago. Got the original license in my early teens. Still remember attaching an antenna to the end of a broom handle and sticking it out the apartment window on Copacabana beach (just slightly against building regs). The history of packet over ham is pretty interesting, just look at AlohaNet. It's been a while since I've been shipboard (other than controlling a 6' R/C sailboat); nice to hear email tech has improved so much. Have you tried any sat stuff?

BTW, if the tech allows it, many email clients allow the download of headers only and upon request the full email. Although I suppose that you may be better off just letting it get down as much as it can...

[skolnick]

Yeah, but those friends will know better:)

Maybe. <grin>

The form doesn't solve the outgoing problem, and that is the tougher one.

It occurred to me that instead of munging with headers I can just grab the body of the message in the filter and generate a new e-mail, killing the original message with exit code 99.

[kitchin]

A web transaction could take fewer bytes. In email, the full headers are longer than most brief messages. Also, the email transaction usually involves getting the index of messages (UIDL), etc. I don't think you can get a message without 5 round trips or so, if latency is an issue.

A web page could be as simple as "<form><textarea name=t></textarea><input type=submit></form>". Then use a server script to parse out from "t" a password, to address and message. The same page could display your messages. I guess you would give your friends one password, and you use another. ???

[skolnick]

A web transaction could take fewer bytes.

Yep, although latency isn't an issue -- bandwidth is. The problem is that while at sea I don't have access to the web. I only have point-to-point connections to Winlink and Sailmail. They both use compression methods unique to the characteristics of radio links. The underlying protocols are even different (AX.25 over PACTOR instead of IP over Ethernet). The connections between the radio network and the Internet are in the shore stations.

To get access to the web I'd need to use a satellite system like Iridium or Globalstar (both $$$) or Inmarsat ($$$$$).

I already have the radio, "modem", and computer equipment for Winlink and Sailmail. The running costs are very low (free for Winlink and $250 / year for Sailmail). The set up meets my needs and has shown itself to be more reliable offshore than the satellite phones.

Last year while crossing the Atlantic, one of my crew had an Iridium phone along. It made his wife more comfortable. Several times he couldn't reach her though, and the connection for e-mail and Internet was awkward. Friends and acquaintances report similar experience with Iridium and even worse issues with Globalstar. The systems were not designed for and are not maintained with clients offshore who have small antennas in mind. The only exception I know is a very technically-minded cruising couple who use Iridium to post articles with magazines and interact with their book publisher.

Inmarsat addresses those issues nicely, although by the time you add a radome to protect the dish of even a mini-M from the extreme environment I'm not sure where you'd put it on my boat.

I appreciate the creative thoughts. Keep 'em coming! I'd love a more elegant solution than the kludge I have come up with.

In the meantime, I have the incoming system I described above working. That was easy. I'm doing research for building the filter now. Depending on work and health stuff I won't possibly be heading offshore again before February and it could well be later.

Now if FQ wants to hire me for development or something so I could cover an Inmarsat terminal and connection minutes all kinds of attractive options open up. I could be the offshore mobile disaster recovery "facility."

[Randall]

Yep, although latency isn't an issue -- bandwidth is. The problem is that while at sea I don't have access to the web. I can't claim to understand how the ship-to-shore part works, so this probably won't help ... but kitchin's suggestion might still work for your outgoing mail if the form script (and the server) is onboard. Or does the Sailmail system control what's in the headers?

Jus' a thought. :winky:

Randall

[skolnick]

First off, you guys are great. You are really making me think, which gets me out of my box.

The whole deal is much like dial-up. Whenever I feel like it (realistically once, twice, or three times a day) I sit down at my laptop and run a propagation model. That gives me a good prediction of which shore radio stations I can reach. I run some client software that controls the modem and radio to try to make a connection.

The shore side networks each have several shore stations that each have multiple frequencies that scan through. Most "listen" to more frequenices than they have radios on a scanning basis, so if someone else is connected then the radio is busy, even if the frequency you are trying to connect on is free.

When you do connect, you download any waiting traffic and upload any outgoing mail.

Incidentally, if you have family or friends in the Peace Corp, they use similar technology (different networks) to communicate in Africa or Southeast Asia. That is why you get e-mail from intermediaries that quotes a message from your friend/family with no direct e-mail address back.

The upshot is that while at sea I have a very limited connection, message-based only, and I need to seriously protect the addresses.

If you don't have enough to do <grin> you can check out http://www.airmail2000.com/ , www.winlink.org , and www.sailmail.com .

[skolnick]

I decided I really like hobbes idea about a form. There will be two ways to reach me at sea: 1. an e-mail address with a whitelist for mail from people I'm expecting to hear from and 2. a web-based form (which I've done before) with image validation ("captcha") for anyone else.

For outbound I'm still working on the filter approach. I haven't made much progress yet (other demands on my time), but the design seems to be gelling in the back of my brain.