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
Related
I have multiple domains pointing at nameservers of a shared hosting platform and manage all the emails of these domains using just one address called hello#domain-a.com as an example.
Because all of these domains work under one business and I don't want to manage multiple accounts, this address also receives all the emails for my other domains domain-b.com and domain-c.com using forwarders.
Sometimes I still need to change the From address, which is why I set up identities in Thunderbird using domain-a.com as the host with hello#domain-b.com and hello#domain-c.com as the From addresses. While doing that, I realized that I didn't need to create these accounts on the mail server and all emails that were sent by either hello#domain-b.com or hello#domain-c.com had a PASS on both SPF and DKIM.
This made me wonder, whether someone else on the same shared hosting platform (whois checkup shows there are more than 600 other domains) could also just use any of my domains to send emails and would get a PASS on both SPF and DKIM, basically making it useless in that specific scenario.
Can anyone on the same shared hosting send emails using my domain with a PASS on both SPF and DKIM?
Why is it possible to use domain-a.com as the host and hello#domain-b.com or hello#domain-c.com as From addresses and still send messages that way? The test messages I have sent using that method don't show domain-a.com but the domain of the From address in their headers. Is this normal behavior? Since I didn't set up any individual accounts for domain-b.com and domain-c.com, I honestly didn't expect this to work.
Thanks in advance.
If someone is on the same shared host as you, they will likely have the same IP address, and so if your SPF includes that IP, they will indeed be allowed to send messages from your domain. The simple solution to that by itself is don't do that – don't put critical content on shared hosting.
The next step is DKIM. DKIM has nothing to do with IP addresses, and sending from a shared host will have no effect, so this is your best defence against this kind of spoofing. A DKIM signature is signed by your private key (which nobody else should be able to access, even on shared hosting – though it is far more at risk there than on your own server). Because they can't see your key, they can't produce DKIM signatures for your domain, and thus messages they try to send from your domain will not contain a valid DKIM signature and they will not be able to get a DKIM pass result.
It could be that your hosting provider is also adding a DKIM signature of their own as an intermediary, though it will match their domain, not yours. You can add your own as well as messages can contain more than one DKIM signature.
To force alignment of From address with the envelope sender (which ends up in a return-path header at the receiver), you need to look at DMARC, specifically the adkim and aspf parameters.
Another approach would be to not send mail through your hosting provider but via some other mail server. This would let you have an SPF record that does not include your hosting provider's IPs. You may find however that you can't do this because low-end hosts tend to block outbound SMTP.
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
We have custom cms that currently sits on a vendor's subdomain, such as cms.vendor.com. It sends email out as coming from user#vendor.com and it seems to be working fine (using Email Queuing + SwiftMailer)
Our vendor asked us to put in the functionality for his users to be able to select from a dropdown, 3-4 other emails address associated with them from other domains he owns. Basically we need to be able to send out emails from our server labeled as being sent from #hisdomains.com, multiple domains.
I am a web programmer and have no clue when it comes to relaying messages. How would I go about being able to send out emails from his other domains? Does he need to setup permissions on his mail servers, or do I need to get into his SMTP servers to send out?
What are some things I should look out for when it comes to SPAM and gmail trusting us?
EDIT:
Not sure if my original question was clear enough. Vendor owns three domains: mysite.com, myothersite.com, mythirdsite.com. He wants a user from our crm to be able to send emails he has on those domains. So my dedicated server will be trying to send an email out as user#mysite.com, user#myothersite.com, and user#mythirdsite.com in the FROM: header.
As long as your server is allowed to send on behalf of a domain your vendor owns, you should not have a problem; just change the From: header to something else when you send out the e-mail.
Stuff like SPF, Sender ID and DKIM have to be properly configured to allow your server to send on behalf of any domain.
See also: http://en.wikipedia.org/wiki/E-mail_authentication
Any domain where the mx record resolves to the same server will work. so user#any.domain will email the same user on the mx contingent server.
To answer your question - just make sure that the mx records in the DNS zone file for each domain name points to the same server as the domain you want to share emails on.
also dependent on server configuration (like shared or whatever) I'm assuming it's dedicated with a simple email server installed. I'm not sure on cPanel/shared servers. but possibly the same.
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.
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.