On 02/04/2010 11:32 AM, Paul McNett wrote: > On 2/4/10 7:58 AM, Leland Jackson wrote: > >> It finally dawn on me, after some sleep last night, and a good, hot cup >> of coffee this morning, that your favorite database admin app would >> probably be Dabo; since, that's kind of your baby. My hat's off to you, >> and Ed, for all you have done in developing Dabo. >> > The AppWizard does a great job for making quick CRUD apps for single-tables, > but you > needed a relationship-auto-finder that AppWizard doesn't do, which is why I > didn't > suggest it. Dabo can certainly handle the normalized structure of that > database, but > the AppWizard can't quickly make an application based on that normalized > structure. > > >> Anyway, I found an article yesterday that explained how to identify a >> roaming user using their email address. Each email address is unique >> with a domain name that resolves to a unique IP address, so this could >> be used to identify an incoming email by have Postfix examine the "From" >> header as trusted for relaying. >> > How can a roaming user's "from" be guaranteed to resolve to a unique ip > address? If > they are in a café, they are likely going over the local wifi where the > router uses > NAT, so everyone in that café has the same external ip address. > > Or are you going to automatically trust for relaying all email that purports > to be > from the stated domain? That opens you up to relaying from everywhere given > the > sender forges the from address. >
The current network to which the iPhone connects, and the corresponding IP address the network assigns to the iPhone computer, are not used to in the "from" header The user would connect to the mail server using their email address, (eg [email protected]) and that would become the email's "from" header. Each valid email address is unique; because, the domain part of the email address resolves to a user who has a mailbox at a unique mail server IP address. The problem with this method of authentication is it is easy to spoof an email address. Spammer are constantly looking for open relays or email server that are not correctly configured. They use spiders and other robots in their search and take over of a mail server. Port sniffer are used to locate computer that have ports open that are normally associated with mail servers. The spammer can then attack the mail server to acquire a user name and password pair that will give them access to the computer. They can then install software on the computer that can easily spoof a valid email address on the mail server, right from with it. Also, if an email address is cracked on a mail server that allows emailing from a remote location, the spammer can send out spam remotely. Then the spammer can connect to the main server remotely to sent out emails by the hundreds of thousands using a spoofed email address. The email list used by spammers usually contain a high percentage of bad addresses, so after they do a spam, email begin bouncing back to the mail server, which is eventually brought to its knees for day on end. There are at least three reason I can think of why spammer uses these methods: 1) They conduct business using resources of others. 2) They are better able to hide their true identity. 3) If the mail server is blacklisted, they make that a problem of somebody else, not them. Although using the "from" header to trust emails for relaying by an email server is not an open relay, its not far from it. LOL The author did not recommend this solution, because it's not secure, but >> I could use this method temporarily for a couple of iPhones, until I had >> the time to implement something more secure, like sasl. >> > The Air Force skipped encryption on their spy drones for the same reason. > > > >> BTW, does anyone know if it's possible to connect a desktop email client >> like Thunderbire to a gmail account? >> > I haven't done it, but in TBird 3 "new account" I see a 'gmail' option. > DBmail has an email list. I'm going to see if anyone on the DBmail list has address the problem of relaying remote/roaming user's email. I'll get back with you then, and let you know what I learn. Regards, LelandJ > Paul > [excessive quoting removed by server] _______________________________________________ Post Messages to: [email protected] Subscription Maintenance: http://leafe.com/mailman/listinfo/profox OT-free version of this list: http://leafe.com/mailman/listinfo/profoxtech Searchable Archive: http://leafe.com/archives/search/profox This message: http://leafe.com/archives/byMID/profox/[email protected] ** All postings, unless explicitly stated otherwise, are the opinions of the author, and do not constitute legal or medical advice. This statement is added to the messages for those lawyers who are too stupid to see the obvious.
