dovecot and postfix, help?

Mike Makuch 1mikemakuch at
Sun Aug 19 20:47:37 EEST 2018

One tip: for checking whether or not you have access to your vps @ 
host:port you ought to use netcat or telnet from your localhost:

I frequently use telnet since you can also type in the protocol to a 
server (assuming the server expects ascii) and get a response out of it. 

     $ telnet 80
Server response:
     Connected to
     Escape character is '^]'.
     GET / HTTP/1.0
Server response:
     <!DOCTYPE html>
         <meta charset="UTF-8" />
         <meta name="viewport" 
content="width=device-width,initial-scale=1,maximum-scale=1" />
       <h1>You are in a twisty maze of passages, all alike.</h1>

And yes in this case "curl" would be more a appropriate utility (for 
http) but not for other protocols that curl doesn't support.

If you telnet to a port that isn't opened and being listened on:

$ telnet localhost 4321
Trying ::1...
telnet: connect to address ::1: Connection refused
telnet: connect to address Connection refused
Trying fe80::1...
telnet: connect to address fe80::1: Connection refused
telnet: Unable to connect to remote host

Good day

On 8/17/18 18:05, Christy S wrote:
> Hi all,
> First a disclaimer. I have played with linux off and on for years, but 
> this is my first time trying to run a server completely on my own from 
> start to finish, well it's on a vps, but still. I'm pretty techie, but 
> a lot of this stuff is new to me, so I apologize for any *duh!* 
> questions. That said, I've so far installed dovecot, postfix, 
> wordpress, and related programs mostly successfully by following 
> tutorials. I say mostly successfully, because I'm having a really hard 
> time trying to get dovecot and postfix to behave together, and I'm 
> about at the end of what I know how to find on google.
> If you're still with me and not groaning at yet another newbie asking 
> wtf did I do wrong questions, thank you! My basic setup is running 
> ubuntu 18 with up to date dovecot and postfix. Sasl is installed, and 
> I'm using a custom domain with all records successfully pointing to 
> the VPS.
> As I mentioned, I've been following tutorials. My goal is to have a 
> mail server which can send and receive emails using this custom domain 
> both from the shell and, much more often, from my primary computer 
> using thunderbird. As there will likely only be two of us using this, 
> I'm completely fine with the setup using mailboxes that actually have 
> linux accounts. I'm also using maildir as the mailbox type. 
> Furthermore, I want to make sure to use ssl on any mail connections.. 
> Normal passwords but ssl being used.
> So, following one tutorial I set up postfix and dovecot, then went to 
> test it. The result was that while on the shell, I could send email to 
> my gmail account from the domain and receive it just fine. I could 
> also send mail from my gmail account to the domain and receive it on 
> the shel. I even managed to get imap to work, so I could receive 
> domain emails in thunderbird, after playing around with tb's settings. 
> However, if using tb I attempted to send an email using the custom 
> domain, smtp failed to connect.
> I verified with my VPS provider that no, they do not block port 25, 
> 465 or 587. I also verified that at&t, my home ISP, does not block 
> outgoing smtp traffic, considering I am using google's for my gmail 
> account. After hitting google again, I realized two things. One, for 
> some reason port 25 never got opened on UFW, so I fixed that. Second, 
> for some reason in all the stuff I did, postfix never got configured 
> to use SSL.
> I found yet another tutorial, and ran through it to set up SSL with 
> postfix. However, in doing this I had to change a path for sasl, only 
> to find out later that doing that broke dovecot! Imap completely and 
> utterly stopped behaving.
> Back to google again, and this time I found something a bit more up to 
> date which explained how to interconnect postfix and dovecot. It goes 
> through using mysql too, but I don't need that, so I skipped that 
> part. Changed the sasl path back to what it should be, told dovecot 
> and postfix to talk to each other and... Nope, still nothing.
> I saw a warning that I should not use different certificates for 
> postfix and dovecot, so I told dovecot to look at the smtpd 
> certificate that I made. Not sure if that's what's breaking this or 
> something completely different, as I'm also brand new to the ssl 
> certificate creation process. So, here's the current status of using 
> thunderbird with my domain.
> mail sent from gmail to new domain, never comes back in thunderbird 
> but doesn't bounce, either.
> Mail sent via thunderbird to gmail from domain, works, but shows up as 
> from my gmail domain as well, which makes me think it's defaulting to 
> the gmail account even though the domain's smtp info is set up. This 
> could be because just before writing this message, I got the accept 
> this certificate dialog over and over again for the domain and had to 
> cancel out of it.
> One final point. I looked at /var/log/mail.log and, while at first I 
> found an error in the path to one of the certificates, once I fixed 
> that no error shows up. I restarted both postfix and dovecot, tried 
> refreshing thunderbird and still no emails showed up. I see the 
> connection in the log, but no errors.
> Anyone have ideas? Even maybe just point me in the right direction for 
> what to check?

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