forum.excito.org

I now own a B3, time to play

I think I might have started on the wrong tack here but I got curious about email. Email behind the front end of clicking "Send" or "Receive" is dammed complicated. There are a few HowTo articles on the wiki about sending emails which I have to implement but I'm using gmail's smtp server and it works. What about receiving emails to mydomain.com? I can already send email from my account through gmail but what if I wanted a new email address? In order to play with this you could set up a dynamic dns domain but I read somewhere that the Internet don't like mail servers with a dynamic IP addresses and black list them On my current ISP I couldn't get a fixed IP address without company details and a business account. Apparently IP4 addresses are quite rare these days. Did nobody think of that happening? Well OK ATM (20 years ago) was meant to address that problem (which didn't get much attention, suited the carriers and not the end user perhaps), and then the IETF produced IPv6 to address that problem. Still I'm running on IPv4, after all these years. Is there an older protocol in widespread use? Even the Navy got rid of Morse

Regardless of that potential problem of fixed IP address, how would you do it? There was a recent security story where a wired writer had his apple devices hacked by somebody ringing in to Apple support to request a password reset. At the root of the problem is that Internet security relies on a login based on email Address & password. We secure our passwords but if we rely on two part security and one part is an email address that's not much security in that element. In the case of wired writer his email addresses were always johnsmith@... So it was pretty easy to predict his username with Apple. Then just ring apple and ask for a password reset. Confirm who you are with a Birthday or something, Bob is your Uncle, Security would be having a different email address for every account. For years we've been pushing a different password for every account we'll soon be going even more complicated.

I'm going completely off my own topic there altogether. I need help assuming I had a fixed IP address or if dynamic addresses worked if I set up dynamic dns on my B3 mydomain.com and I set up postfix on my B3 postfix would receive email for the domain and store it in the ~/maildir/ directory. Lets not overcomplicate things with multiple email addresses but if I had one email address an external smtp server, say google's smtp server, on receiving an email for me@mydomain.com would connect to my B3 and transfer the email. Postfix would accept it and stick the new email in ~/maildir/

On my various phones and laptops I'd have to point my mail clients to B3:~me/maildir/ via IMAP is that another part of postfix, or plugin or completely different program which takes care of syncing maildir to the various devices? OK that's another question. If I saw something going into my B3 ~me/maildir/ I'd be stoked.

As I said at the start maybe I started playing with the wrong Toy in my B3. Apache is probably much easier but I'll get to that in time. I know I have to read a lot lot more and i have a postfix book I'm reading through but a lot of the book is lists of /etc config details. Sleep..zzzzzzz If I ever get my head around this the B3 community will have a HowTo posted by me@mydomain.com

Back to the books

arigead wrote:In order to play with this you could set up a dynamic dns domain but I read somewhere that the Internet don't like mail servers with a dynamic IP addresses and black list them On my current ISP I couldn't get a fixed IP address without company details and a business account.

I'm afraid that blacklisting is justified. Nearly all mails from dynamic addreesses is spam. As a mail-admin my opinion is that, if you're not professional enough to obtain a fixed IP address, you're not professional enough to send me emails.

arigead wrote:Apparently IP4 addresses are quite rare these days. Did nobody think of that happening? Well OK ATM (20 years ago) was meant to address that problem

Well, the problem is that IPV6 still does not make business sense as the clients need to be converted before the servers. As almost no DSL providers give IPV6, there are only downsides on employing it at the server end.

arigead wrote: I need help

THen you should pose a question and not post a thesis on Apple security flaws that are unrelated to the rest of the post.

arigead wrote:but if I had one email address an external smtp server, say google's smtp server, on receiving an email for me@mydomain.com would connect to my B3 and transfer the email. Postfix would accept it and stick the new email in ~/maildir/

yes, but you need to tell postfix that it may accept mail for your domain.

arigead wrote:On my various phones and laptops I'd have to point my mail clients to B3:~me/maildir/ via IMAP is that another part of postfix, or plugin or completely different program

This is handled by the IMAP server (dovecot or Cyrus or something), it is not part of postfix.

arigead wrote:Apache is probably much easier but I'll get to that in time.

It is also not a mail server.

arigead wrote:I know I have to read a lot lot more and i have a postfix book I'm reading through but a lot of the book is lists of /etc config details.

Well the /etc/postfix/main script is where the postfix action is. But unless you're setting yourself up to be a mailadmin for a big company, there is not much point in reading that book beyond the first few chapters.

Thanks for all the info. Very helpful. I know Apache is a web server and was merely suggesting that would have been an easier place to start, with a web server.

But thanks for the info on black listing of dynamic IPs. I don't want to get into professional/amateur, but you suggested that I have no business sending email, which I'm happy as Larry with because that means that I could possibly set up gmail smtp server on the sending side. It currently sends email for all my various accounts but set up postfix for receiving email to me@mydomain.com or anything@mydomain.com. Does that sound reasonable?

I've never had a problem with blacklisting and I use a dynamic IP address (my ISP doesn't supply static ones, unfortunately).

However, I don't use my B3 for SMTP so outgoing mail does always come from a static IP (the SMTP server owned by the ISP) so that might explain it.

Nearly all isps offer free smtp hops for their clients. Postfix has a default setting that uses this, so that all mails you sent are forwarded to the isp smtp server. The benefit is that, if you use google smtp, all mail is rewritten as yourname@gmail.com

I'd be very amazed if people would block delivering emails to a suspicious domain. If they originate from such a domain that would be something different of course. Similar for an IP that has previously been redflagged as a spam source and is now yours. However in most dynamic pools you'll most likely find that the SMTP protocol is either limited or completely blocked and this is the protocol that you will need to either send or receive email.

Now services like Gmail use a different client port for SMTP communication and that will circumvent the ISP block. That is something that you can't do. So first objective is to verify that you can actually use SMTP (TCP port 25). Then the next step is to get yourself a domain and a provider that allows you to edit the domain contents - as a rule this means that it will have to be a paid domain. In the domain editor you will then need to assign a server that accepts mail for your domain by adding an MX record (yes: this can be a server in a different domain).

In my case I have two MX records: the first one points to my own server with a priority of 10 and the second one points to my ISP's mailhop server with a priority of 100 (which is lower). The reason is that my ISP blocks both outgoing and incoming SMTP traffic so their mailhop server is the only one that can access my server (the B3).