jet10000 / forward-email

:envelope: :fast_forward: ForwardEmail is a free, encrypted, and open-source email forwarding service for custom domains. Visit our website to get started.

Forward Email

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ForwardEmail is a free, encrypted, and open-source email forwarding service for custom domains at http://forwardemail.net

Table of Contents

• How It Works
• Send Mail As Using Gmail
• Issues & Debugging
• Timeline
• Self-Hosted Requirements
• Programmatic Usage
• Service-Level Agreement
• Terms of Use
• FAQ
  • Why did I create this service
  • Can I forward emails to multiple recipients
  • Can I have multiple global catch-all recipients
  • Is there a maximum limit on the number of email addressess I can forward to
  • Can I recursively forward emails
  • Can people unregister or register my email forwarding without my permission
  • How is it free
  • What is the max email size limit
  • Can I forward my emails from a well-known provider
  • Do you store emails and their contents
  • Do you store logs of emails
  • Can you read my forwarded emails
  • Does it support the + symbol (e.g. for Gmail aliases)
  • Does this forward my email's headers
  • Is this well-tested
  • Do you pass along SMTP response messages and codes
  • How do you prevent spammers and ensure good email forwarding reputation
  • Can I "send mail as" with this
  • Can I forward unlimited emails with this
  • How do you perform DNS lookups on domain names
  • How fast is this service
• Contributors
• License

How It Works

IMPORTANT NOTE: Replace [e-mail] below with the email address you want to forward emails to:

1. Set the following DNS MX records on your domain name (having both is required):

Name/Host/Alias	TTL	Record Type	Priority	Value/Answer/Destination
@ or leave blank	3600	MX	10	mx1.forwardemail.net
@ or leave blank	3600	MX	20	mx2.forwardemail.net

Note that there should be NO other MX records set on your domain name. If there were already MX records that existed, please delete them completely.

2. Set (and customize) the following DNS TXT records on your domain name:

If you are forwarding all emails from your domain, ([e-mail], [e-mail], etc) to a specific address [e-mail]:

Name/Host/Alias	TTL	Record Type	Value/Answer/Destination
@ or leave blank	3600	TXT	forward-email=[e-mail]

If you just need to forward a single email address (e.g. [e-mail] to [e-mail]; this will also forward [e-mail] to [e-mail] automatically):

Name/Host/Alias	TTL	Record Type	Value/Answer/Destination
@ or leave blank	3600	TXT	forward-email=hello:[e-mail]

If you are forwarding multiple emails, then you'll want to separate them with a comma:

Name/Host/Alias	TTL	Record Type	Value/Answer/Destination
@ or leave blank	3600	TXT	forward-email=hello:[e-mail],support:[e-mail]

As of November 2, 2018 we now have added support for multi-line TXT records! You can now have an infinite amount of forwarding emails setup – just make sure to not wrap over 255 characters in a single-line and start each line with forward-email=. An example is provided below:

Name/Host/Alias	TTL	Record Type	Value/Answer/Destination
@ or leave blank	3600	TXT	forward-email=hello:[e-mail],support:[e-mail]
@ or leave blank	3600	TXT	forward-email=help:[e-mail],foo:[e-mail]
@ or leave blank	3600	TXT	forward-email=orders:[e-mail],baz:[e-mail]
@ or leave blank	3600	TXT	forward-email=info:[e-mail],beep:[e-mail]
@ or leave blank	3600	TXT	forward-email=errors:[e-mail],boop:[e-mail]

3. Set (and customize) the following SPF record for SPF verification for your domain name (this will allow SPF verification to pass, note that you may need to enclose this value in quotes if you are using Amazon Route53):

Note that if you are using a service such as GoDaddy, you will need to use a TXT record type instead of an SPF record for this step.

If you're using a service like AWS Route 53, then edit your existing TXT record and add the following as a new line:

Name/Host/Alias	TTL	Record Type	Value/Answer/Destination
@ or leave blank	3600	SPF	v=spf1 a mx include:spf.forwardemail.net -all

⚠️ If you are using Google Apps, you'll need to append include:_spf.google.com to the value above – e.g. v=spf1 a mx include:spf.forwardemail.net include:_spf.google.com -all.

If you already have a similar line with v=spf1, then you'll need to append include:spf.forwardemail.net right before any existing include:host.com records and before the -all in the same line (e.g. v=spf1 a mx include:spf.forwardemail.net include:host.com -all).

Note that there is a difference between -all and ~all. The - indicates that the SPF check should FAIL if it does not match, and ~ indicates that the SPF check should SOFTFAIL. We recommend to use the -all approach to prevent domain forgery.

4. Send a test email to confirm it works. Note that it might take some time for your DNS records to propagate.

5. Add [e-mail] to your contacts. In the event that someone is attempting to send you an email that has a strict DMARC record policy of reject or quarantine, we will rewrite the email's From header with a "friendly-from". This means the From will look like Sender's Name <[e-mail]> and a Reply-To will be added with the original sender's From address. In the event that there is already a Reply-To set, we will not overwrite it.

6. If you wish to "Send Mail As" from Gmail, then you will need to follow the steps under Send Mail As Using Gmail below.

---

Optional Add-ons:

• Add a DMARC record for your domain name by following the instructions at https://dmarc.postmarkapp.com (this will allow DMARC verification to pass)
• If the email lands in your spam folder (which it should not), you can whitelist it (e.g. here are instructions for Google https://support.google.com/a/answer/60751?hl=en&ref_topic=1685627)
• Add the ability to "Send Mail As" from Gmail by following Send Mail As Using Gmail below

Send Mail As Using Gmail

After you've followed the steps above in How It Works you can follow these steps in Gmail in order to "Send Mail As" using your custom domain.

1. Assuming you are using Gmail's Two-Factor Authentication (strongly recommended for security), visit https://myaccount.google.com/apppasswords.
2. When prompted for Select the app and device you want to generate the app password for:
   • Select Mail under the drop-down for Select app
   • Select Other under the drop-down for Select device
   • When prompted for text input, enter your custom domain's email address you're forwarding from (e.g. [e-mail] - this will help you keep track in case you use this service for multiple accounts)
3. Copy the password to your clipboard that is automatically generated

   ⚠️ If you are using Google Apps, visit your admin panel Apps > G Suite >Settings for Gmail > Advanced settings and make sure to check "Allow users to send mail through an external SMTP server...". There will be some delay for this change to be activated, so please wait for ~5-10 minutes.

4. Go to Gmail and under Settings > Accounts and Import > Send mail as, click Add another email address
5. When prompted for Name, enter the name that you want your email to be seen as "From" (e.g. Niftylettuce)
6. When prompted for Email address, enter the email address with the custom domain you used above (e.g. [e-mail])
7. Click Next Step to proceed
8. When prompted for SMTP Server, enter smtp.gmail.com and leave the port as 587
9. When prompted for Username, enter the portion of your Gmail address without the @gmail.com part (e.g. niftylettuce if my email is [e-mail])
10. When prompted for Password, paste from your clipboard the password you generated in step 2 above
11. Leave the radio button checked to Secured connection using TLS
12. Click Add Account to proceed
13. Open a new tab to Gmail and wait for your verification email to arrive (you will receive a verification code that confirms you are the owner of the email address you are attempting to "Send Mail As")
14. Once it arrives, copy and paste the verification code at the prompt you received in the previous step
15. Once you've done that, go back to the email and click the link to "confirm the request". You need to do this step and the previous step for the email to be correctly configured.
16. Done!

Issues & Debugging

The most probable cause of your issues with not receiving test emails or with configuration in general is due to DNS propagation and caching.

Fortunately our DNS provider Cloudflare has a nice "Purge Cache" tool available for you to use at https://1.1.1.1/purge-cache/.

All you need to do is go to that link for both "MX" and "TXT" record types, enter your domain name, and click "Purge Cache". You'll then need to wait a few minutes and try again!

Timeline

• May 6, 2019: @niftylettuce refactored the project thanks to @andris9 and released v2 with major performance gains
• November 5, 2017: @niftylettuce released v1 of the project, with a focus to always be completely open source, transparent, private, secure, and free
• 2010-2017: @niftylettuce grew weary from the headache of setting of mail servers for every domain or the hassle and costs of using services Google Business and Zoho

Self-Hosted Requirements

You'll need a server with Ubuntu, so we recommend Digital Ocean, as it only costs $5/mo for a basic droplet.

You'll also need the following dependencies installed:

• Node.js (v8.3+) - use nvm to install it on any OS (this is what runs the email forwarding service)

  • After installing nvm you will need to run nvm install node
  • We also recommend you install yarn, which is an alternative to npm

• Redis (v4.x+) - this is a fast key-value store database used for rate-limiting and preventing spammers

  • Mac (via brew): brew install redis && brew services start redis

  • Ubuntu:

    sudo add-apt-repository -y ppa:chris-lea/redis-server
    sudo apt-get update
    sudo apt-get -y install redis-server

  If you ever need to completely wipe rate-limiting records, run redis-cli and then type the command FLUSHALL

• SpamAssassin - this is used to scan emails for spam (if it is not installed/detected it will not be used)

  • Ubuntu:

    sudo apt-get -y install spamassassin spamc python

    If you are using a jessie based version of Debian (e.g. Ubuntu 16.04):

    systemctl enable spamassassin

    This is due to the bug identified here: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=764438

    You must follow the remainder of instructions here to enable it and setup automatic rule updating: https://www.digitalocean.com/community/tutorials/how-to-install-and-setup-spamassassin-on-ubuntu-12-04

• ufw - recommended for security on Ubuntu server

  • Ubuntu:

    sudo apt-get -y install ufw

    # allow port 22
    sudo ufw allow ssh
    # allow port 25
    sudo ufw allow smtp
    # allow port 465
    sudo ufw allow smtps
    # allow port 587
    sudo ufw allow submission
    # turn on rules
    sudo ufw enable

• authbind - for allowing non-root users to run on restricted ports

  • Ubuntu:

    sudo apt-get install authbind

    Modify user with the name of your user running the email forwarding server:

    sudo touch /etc/authbind/byport/25
    sudo chown user:user /etc/authbind/byport/25
    sudo chmod 755 /etc/authbind/byport/25
    sudo touch /etc/authbind/byport/465
    sudo chown user:user /etc/authbind/byport/465
    sudo chmod 755 /etc/authbind/byport/465
    # note that ports in range 512-1023 need ! added
    # <http://manpages.ubuntu.com/manpages/xenial/man1/authbind.1.html>
    sudo touch /etc/authbind/byport/\!587
    sudo chown user:user /etc/authbind/byport/\!587
    sudo chmod 755 /etc/authbind/byport/\!587

• pm2 - for managing and running all processes

  • npm: npm install -g pm2
  • yarn: yarn global add pm2

• openssl - for generating DKIM keys for your domain

  • Ubuntu: sudo apt-get install openssl

    See https://lxadm.com/Generating_DKIM_key_with_openssl to generate a DKIM key.

    Your DNS TXT record name/host/alias should be default._domainkey (if you change this you'll also need to change this value via an environment flag override, see the source code for more info).

    Your DNS TXT record value should look something like this (replace the p= part with your actual public key generated from the above link):

    "v=DKIM1; k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCojharU7eJW+eaLulQygsc/AHx2A0gyLnSU2fPGs8mI3Fhs3EVIIRP01euHg+IljMmXz9YtU+XMfZuYdSCa9NY16XjoIgub2+lkeiHHNpURIpwQJSeHxviMOfMAZ5/xSTDDoaYY2vcKytheZeLAVK2V1SuTdTp+C6B9E6AUSu1TwIDAQAB"
    

• python-spfcheck2 - for validation of SPF records, see its requirements for more information

• python-dkim-verify - for validation of DKIM signatures, see its requirements for more information

• DNS records - you need to setup and modify your DNS records with your own self-hosted version. See How It Works (obviously replace forwardemail.net with your own domain - and make sure you do DNS lookups for all related subdomains such as mx1.forwardemail.net, mx2.forwardemail.net, and spf.forwardemail.net – and clone them with your own). We recommend using Amazon Route 53 for DNS hosting.

• Reverse DNS ("rDNS") with PTR Record- - the PTR record for your server's IP address is controlled by your server provider, and therefore you need to contact your server provider to set the PTR record for you. Services such as DigitalOcean will set a PTR record for you automatically as long as you use a fully-qualified domain name ("FQDN").

• FQDN - you'll need to set your server up to have a FQDN, you can do this by:

  sudo vim /etc/hosts

  -127.0.1.1 current-hostname
  +127.0.1.1 domain.com

  sudo vim /etc/hostname

  +domain.com

• Nameservers - we highly recommend you set your server's nameservers to 1.1.1. (see "How do you perform DNS lookups on domain names" below and here is a Digital Ocean guide)

Programmatic Usage

npm:

npm install forward-email

yarn:

yarn add forward-email

const ForwardEmail = require('forward-email');
const os = require('os');

const config = {
  noReply: '[e-mail]',
  exchanges: ['mx1.forwardemail.net', 'mx2.forwardemail.net'],
  ssl: {},
  dkim: {}
};

if (process.env.NODE_ENV === 'production') {
  config.ssl = {
    secure: process.env.SECURE === 'true',
    key: fs.readFileSync('/home/deploy/mx1.forwardemail.net.key', 'utf8'),
    cert: fs.readFileSync('/home/deploy/mx1.forwardemail.net.cert', 'utf8'),
    ca: fs.readFileSync('/home/deploy/mx1.forwardemail.net.ca', 'utf8')
  };
  config.dkim = {
    domainName: 'forwardemail.net',
    keySelector: 'default',
    privateKey: fs.readFileSync('/home/deploy/dkim-private.key', 'utf8'),
    cacheDir: os.tmpdir()
  };
}

const forwardEmail = new ForwardEmail(config);
forwardEmail.server.listen(process.env.PORT || 25);

Service-Level Agreement

This project is currently a best-effort service, however note that the creators of this service also use it themselves – so you can expect reliability and security. However this is not a binding nor enforceable SLA and again, this is a best-effort service.

Terms of Use

This software and service uses the MIT License (see LICENSE).

Here's the relevant excerpt regarding its terms of use:

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

FAQ

Why did I create this service

I created this service after realizing that the only email forwarding services that exist now that are "free" are also closed-source and proprietary. This means they probably read your forwarded emails.

Before creating this, of course I adhere to the "don't repeat yourself" practice - so I endlessly searched on StackOverflow, GitHub, Gists, and elsewhere for alternative solutions.

Of course there's Haraka, sendmail, postfix, and dozens of other options, but they require a lot of setup, configuration, testing, maintenance, and are not simple. The current service offering for email forwarding is either extremely bloated, insecure, requires payment, has a convoluted setup with unsolved or undocumented bugs (that lead you down a rabbit hole of searching for hours to come up empty handed), or they're closed-source.

There's also solutions that use "serverless" technologies, such as through Amazon SES and Amazon Lambda, but again they are extremely confusing, time intensive, and no typical user I know would go to those lengths for setup (and instead would probably end up using a simpler alternative as I almost did; in exchange for lack of privacy).

Furthermore, solutions like Amazon SES do not allow you to modify the envelope of the SMTP request, therefore you will need to do an ugly Reply-To field and rewrite the From as well to something like [e-mail] (which is really not clean).

Then there's Gmail, which costs money now for custom domains (it used to be free). They also don't allow you to easily set up email forwarding for custom domains anymore.

There's also Zoho mail, but again that requires you signing up for an account with Zoho, and then forwarding over the emails in a configuration setting.

Put simply, there was no current email-forwarding service that was free, simple, secure, tested, and open-source.

This service solves all of these problems.

Can I forward emails to multiple recipients

Yes, absolutely. Just specify multiple recipients in your TXT records.

For example, if I want an email that goes to [e-mail] to get forwarded to [e-mail] and [e-mail], then my TXT record would look like this:

Name/Host/Alias	TTL	Record Type	Value/Answer/Destination
@ or leave blank	3600	TXT	forward-email=hello:[e-mail],hello:[e-mail]

Or, you could specify them in two separate lines, such as this:

Name/Host/Alias	TTL	Record Type	Value/Answer/Destination
@ or leave blank	3600	TXT	forward-email=hello:[e-mail]
@ or leave blank	3600	TXT	forward-email=hello:[e-mail]

It's up to you!

Can I have multiple global catch-all recipients

Yes, you can. Just specify multiple global catch-all recipients in your TXT records.

For example, if I want every email that goes to *@niftylettuce.com (the asterisk meaning its a wildcard aka catch-all) to get forwarded to [e-mail] and [e-mail], then my TXT record would loo like this:

Name/Host/Alias	TTL	Record Type	Value/Answer/Destination
@ or leave blank	3600	TXT	forward-email=[e-mail],[e-mail]

Or, you could specify them in two separate lines, such as this:

Name/Host/Alias	TTL	Record Type	Value/Answer/Destination
@ or leave blank	3600	TXT	forward-email=[e-mail]
@ or leave blank	3600	TXT	forward-email=[e-mail]

It's up to you!

Is there a maximum limit on the number of email addressess I can forward to

Yes, the default limit is 10. You could have hello:[e-mail], hello:[e-mail], hello:[e-mail], … (from 1-10) – and any emails to [e-mail] would get forwarded to [e-mail], [e-mail], [e-mail], … (from 1-10).

Can I recursively forward emails

Yes, you can, however you still must adhere to the maximum limit. If you have hello:[e-mail] and nick:[e-mail], then emails to [e-mail] would get forwarded to [e-mail] and [e-mail]. Note that an error will be thrown if you attempt to recursively forward emails.

Can people unregister or register my email forwarding without my permission

We use MX and TXT record verification, therefore if you add this service's respective MX and TXT records, then you're registered. If you remove them, then you're unregistered. You have ownership of your domain and DNS management, so if someone has access to that then that's a problem.

How is it free

I built this for myself and use it regularly. I feel bad that people are using free closed-source forwarding services and risking their privacy and security. I also know that most of these services if not all of them don't offer all the features that come with mine. If this thing really takes off I might ask for donations or do a pay-what-you-want model to cover server costs.

What is the max email size limit

We default to a 25 MB size limit (the same as Gmail), which includes content, headers, and attachments.

An error with the proper response code is returned if the file size limit is exceeded.

Can I forward my emails from a well-known provider

No, we don't support forwarding from your Gmail to another Gmail (this is just an example).

Most email service providers like Gmail, Yahoo, Hotmail, Zoho, etc. already have this feature built-in for you to use.

Do you store emails and their contents

No, absolutely not.

Do you store logs of emails

No, absolutely not.

Can you read my forwarded emails

No, I cannot read your emails and I have no wish to. Many other email forwarding providers unethically read your email. This is not what I'm about.

The code that is deployed to the server is publicly visible on GitHub!

Does it support the + symbol (e.g. for Gmail aliases)

Yes, absolutely.

Does this forward my email's headers

Yes, absolutely.

Is this well-tested

Yes, it has tests written with ava and also has code coverage.

Do you pass along SMTP response messages and codes

Yes, absolutely. For example if you're sending an email to [e-mail] and it's registered to forward to [e-mail], then the SMTP response message and code from the gmail.com SMTP server will be returned instead of the proxy server at mx1.forwardemail.net or mx2.forwardemail.net.

How do you prevent spammers and ensure good email forwarding reputation

Per documentation and suggestions from Google at https://support.google.com/a/answer/175365?hl=en, along with best practice, including:

1. DNSBL - we test senders IP's against the zen.spamhaus.org DNS blacklist

2. SpamAssassin - using spamc client to check emails and automatically reject them if they're marked as spam

   • Checks daily for updated rules
   • Spam score threshold of 5.0
   • Uses bayes theorem and auto learning
   • Uses other improvements

3. SPF/DKIM - through checking if an SPF record exists for a sender, and if so, we reverse-lookup the SMTP connection's remote address to validate it matches the SPF record, otherwise it's rejected. If an SPF record does not exist, then we require DKIM verification. If DKIM headers are passed and fail, then it is rejected as well. If no DKIM headers are passed, then we assume that DKIM validation passes.

4. MX - through checking if the sender's from address domain has MX records (so it's actually coming from a mail exchange/SMTP server), otherwise it's rejected

5. Disposable Email Addresses - we automatically block senders that are from the disposable-email-domains list

6. FQDN - validates that senders SMTP connections are from FQDN (meaning no IP addresses, they must have a valid domain name resolved)

7. TXT - through checking if the email address the sender is trying to send to has a TXT DNS record with a valid email forwarding setup

8. DMARC - we check if a DMARC record exists from the sender's FQDN, and if so, if it is reject or quarantine then we re-write the From of the email as a "friendly-from". This means the From is set to $originalName <[e-mail]> ($originalName is the original From name, e.g. "John Doe" in "John Doe [e-mail]"). Furthermore we set a Reply-To (if one is not already set) of the original sender's from address.

Can I "send mail as" with this

Yes! As of October 2, 2018 we have added this feature. See Send Mail As Using Gmail above!

Can I forward unlimited emails with this

Practically yes - the only current restriction is that senders are limited to sending 200 emails per hour through the system.

If this limit is exceeded we send a 451 response code which tells the senders mail server to retry later.

How do you perform DNS lookups on domain names

We use CloudFlare's privacy-first consumer DNS service (see announcement here). Note that the Python packages we use (python-spfcheck2 and python-dkim-verify) do not have the means like Node.js does with dns and its method dns.setServers – therefore we set the server DNS to 1.1.1.1 which it will use as a fallback in this case.

How fast is this service

The latest version, v2 (released on May 6, 2019) was a major rewrite from v1 and focuses on performance through streams. Nodemailer's prolific author Andris Reinman (@andris9) helped us switch off using the mailparser library and use mailsplit instead with some custom transform logic to split the header and the body of the message without affecting the body. This allows us to perform operations on headers very fast (such as security checks and for SPF/DKIM/DMARC compliance).

In other words, the latest version of this service services uses streams purely now and is lightning fast. The older version v1 also had some logic not in the most optimal order of operations – but now v2 does less memory/network intense operations first (and returns early if possible to send a response as quickly as possible to the SMTP client).

At no point in time do we write to disk or store emails – everything is done in-memory thanks to Node.js's streams and transforms! 🎉

Contributors

Name	Website
Nick Baugh	http://niftylettuce.com/

License

MIT © Nick Baugh