Setting up catchall email for testing purposes - email

Is there a way to set up test email server that would have catchall mail, without actual owned domain (e.g some fake domain)? If so, can someone write it how
I would like to have such server for testing purposes, because I don't want to use real email server with real catch all mail to test some things (real one is used in production).
Is it possible to, for example create such mail locally, so it would behave like a real mail server (even if only locally).
For example define test#mydomain.com email to treat as catch all mail that would take any message which is written in *#mydomain.com (let say there are no other mail boxes)

Easily done: Configure the mail server as though you own the domain, without owning the domain. Add it to your local hosts files and/or nameservers.
Note, though: Make sure you pick a domain that doesn't exist. If you pick google.com and send lots of mail to "your" sergey#google.com, you're setting yourself up to make a mistake and deliver mail to the real Google.

Related

Email server to receive email from any account within domain and ideally alias

I'm currently testing some complicated functionality in a web app that involves multiple accounts within the app; each with its own unique email address. I have a few temp gmail accounts that I'm using for this purpose, but keep having to update email addresses in the database to something else for some accounts in order to reuse email addresses. It gets meesy very quickly.
My question is; is there a way I can setup an email server on my VPS (Ubuntu 16.04) that is able to accept all email addresses on a given domain without me having to define each one in advance? Ie; I'd like to be able to make up email addresses as I go; test1#mydomain.com, test2#mydomain.com, etc, and have the server receive AND store any incoming emails to those addresses. Emails include account verifications, notifications, etc, and I need to know what is being sent to each participant at each point in each workflow as I test.
Ideally I'd like some way to view all of these emails on the domain regardless of address. Perhaps setting up an alias using some kind of wildcard so that all incoming email go to a single address that I can configure in my email client on my dev machine.
Consider rewriting envelope recipient x#subdomain.example.net to handler+x#example.net
AFAIR sendmail, postfix and exim support such rewrites. AFAIR all three support passing +detail as parameter to procmail script (to ~handler/.procmailrc as $1).
WARNING: test handling message to multiple special recipients.
Post which specific SMTP/MTA server do you use if you want more hints.
Gmail also supports plussed addresses BUT you get reliable hint about original recipient only for message to single special/plussed recipient.
After a lot of research and messing about with different configurations, I found the best solution for me was PostFix with Dovecot.
I was able to set up virtual mailboxes in PostFix with virtual_mailbox_maps pointing to a file that contained this; #mydomain.com mydomain.com/catchall/
This allows mail to any email address within the domain to go to one mailbox. The mydomain.com/catchall/ is a location on the server where the mailbox is located. By convention, the domain is used in the path. Useful if you are hosting email on multiple domains. Dovecot supports variables in the config which allows you to point it to the correct mailbox.
I also found that the PostFix main.cf file must have mydestination = localhost for this configuration to work.
the following posts helped me getting this up and running;
https://www.digitalocean.com/community/tutorials/how-to-set-up-a-postfix-e-mail-server-with-dovecot
https://www.digitalocean.com/community/tutorials/how-to-install-and-setup-postfix-on-ubuntu-14-04

Postfix Mail Relay - Only permit sending to specific emails

I am learning how to configure postfix. I would like to setup a mail relay to only forward emails for specific recipients email addresses and block, or even better redirect to the block addresses to generic account for investigation.
The relay will be used in a development environment and I want to ensure that production emails addresses are not accidentally used in development or testing. As a specific example I would like to create a list of emails address recipients that mail is permitted to be forwarded to eg:
dev#example.com
test#example.com
Block any other address that the relay is asked to forward for example.com. Ideally I would like to forward all blocked to an account check#example.com to investigate.
Could some one point me to the section of the postfix configuration file I should look into?
Thanks
Densha
You'll have to do a couple parts to the setup.
Part 1 is your allowed list. What emails are allowed to be sent out. If this list will change frequently you'll want to look into using an external lookup like mysql for this. If you use flat files in the postfix configuration directory then you'll have to restart postfix for each change. With mysql it will perform a new lookup each time, no restart. Postfixadmin is a tool that may help in this case.
For your 2nd problem of redirecting all mail to another account for investigation see this other solution.
https://serverfault.com/questions/144325/how-to-redirect-all-postfix-emails-to-one-external-email-address

Basic understanding of SMTP: mail from

I'm implementing an application in ruby on rails (although this is a minor detail) that needs to send emails. Everything works fine, but I'm surprised cause when the app sends a mail, as long as it's authenticated against the smtp server, the sender it's going to be whatever it's specified in mail from. My point is, I can authenticate in a smtp server with "myuser#mydomain.com" and "mypassword" and be able to send a mail in which the recipient would see whichever address I want as sender.
This doesn't make any sense for me, and I'm sure it can't be so easy. I know it's surely a completely silly question for most of you, but would really appreciate anyone could make it clear for me.
Cheers!!
You authenticate as a generic user, it is only an accident that your login name is similar to a mail address. And yes, usually you can send mail with any reverse-path (reverse-path is the address in the MAIL FROM SMTP command). This may be necessary, for example a list manager uses VERP and sends mails with many unique reverse-paths.
However, some mail servers and mail administrators do place restrictions on the reverse path and the address in the From header. Especially, if the server signs the message.
Moreover, if the receiving server checks SPF records, it is useless to impersonate a remote domain, even if it is allowed, because the mail will be rejected anyway (if the domain publishes an SPF DNS record).

Accepting emails from domain with wildcard subdomain

I'm setting up an app to preform mailhooks. You create an account, assign a callback url, and a pattern to match. Then you get a subdomain that you can send email to. Something like accountname.mail.appdomain.com.
This is how it might work.
Pattern: ^(?P\w+)-reply$
Account: accountname
Callback: http://www.someotherapp.com/reply/create/
If someone sends an email to 12345-reply#accountname.mail.appdomain.com I need to be able to collect that email in I guess a catch all mailbox. Then have a background job that fetches mail and routes them based on the TO address and custom domain.
The problem I am running into is how to get the email server to accept these incoming emails. Right now I have a MX record set up that points from *.mail.appdomain.com to mx1.emailsrvr.com and mx2. When I "dig" I get the correct routing however I don't think the email server is set up to accept the incoming mail.
If this is not possible another option I have been playing with is creating a python smtp server using the built-in smtp lib. All this server would do is accept incoming requests to port 25 and place the mail in a queue. I have that working fine I'm just worried that not using a real smtp server might create problems.
BTW: The main server will be running on slicehost, if that matters.
ALSO: This server is not going to be sending email from these custom domain, if that matters.
What you need is a dynamic configuration of your mail server, right? Then this depends on your mail server capabilities.
If you use Postfix then you could add virtual domain setup being configured in MySQL tables. Or other databases. From within your application you then only need to add/remove rows in these tables to accept only the valid domains.
Same goes for Exim which is even more extensible.

Development SMTP Server

I need a cross platform (at least windows and mac) development utility that runs as an SMTP server that acts as an SMTP server but will redirect all mail to a single address that's configurable. It would also be helpful if it wrote the contents out to a file or gui. Long ago I configured Apache James to do this but it wasn't that straight forward to figure out. Hoping there's something really simple out there.
I need the emails to be forwarded (to the single address) so I can see how they are rendered on different clients (gmail, outlook, etc.)
Thanks! -Mike
We used Mailtrap for this. It give you remote smtp server account and direct access to all mails in it. So you just enter given smtp credential in your application and after that all email sent by your system will be visible on mailtrap.
On mailtrap you can have as many smtp account as you want( different account for different application environments, or different application) Also you can manage access to your account ( so only trusted people will se your emails) and you can forward some emails to real email addresses.
It doesn't do the forwarding you are looking for, but for most of my testing I make use of fakemail (http://www.lastcraft.com/fakemail.php) it's simply a script that listens on a port an acts as an smtp server, writing any incoming mail to a directory.
You could use Python's smtpd library and override the process_message function to only send to the desired address -- i.e. replace the "to" field with your desired constant email address.
Here's a page with some examples of using smtpd (with asyncore) to actually send out mail.