App

SimpleLogin | Protect your online identity with email alias

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Your email address is your online identity. When you use the same email address everywhere, you can be easily tracked. More information on https://simplelogin.io

This README contains instructions on how to self host SimpleLogin.

Once you have your own SimpleLogin instance running, you can change the API URL in SimpleLogin's Chrome/Firefox extension, Android/iOS app to your server.

SimpleLogin roadmap is at https://github.com/simple-login/app/projects/1 and our forum at https://github.com/simple-login/app/discussions, feel free to submit new ideas or vote on features.

Prerequisites

• a Linux server (either a VM or dedicated server). This doc shows the setup for Ubuntu 18.04 LTS but the steps could be adapted for other popular Linux distributions. As most of components run as Docker container and Docker can be a bit heavy, having at least 2 GB of RAM is recommended. The server needs to have the port 25 (email), 80, 443 (for the webapp), 22 (so you can ssh into it) open.

• a domain that you can config the DNS. It could be a sub-domain. In the rest of the doc, let's say it's mydomain.com for the email and app.mydomain.com for SimpleLogin webapp. Please make sure to replace these values by your domain name whenever they appear in the doc. A trick we use is to download this README file on your computer and replace all mydomain.com occurrences by your domain.

Except for the DNS setup that is usually done on your domain registrar interface, all the below steps are to be done on your server. The commands are to run with bash (or any bash-compatible shell like zsh) being the shell. If you use other shells like fish, please make sure to adapt the commands.

Some utility packages

These packages are used to verify the setup. Install them by:

sudo apt update && sudo apt install -y dnsutils

Create a directory to store SimpleLogin data:

mkdir sl
mkdir sl/pgp # to store PGP key
mkdir sl/db # to store database
mkdir sl/upload # to store quarantine emails

DKIM

From Wikipedia https://en.wikipedia.org/wiki/DomainKeys_Identified_Mail

DomainKeys Identified Mail (DKIM) is an email authentication method designed to detect forged sender addresses in emails (email spoofing), a technique often used in phishing and email spam.

Setting up DKIM is highly recommended to reduce the chance your emails ending up in the recipient's Spam folder.

First you need to generate a private and public key for DKIM:

openssl genrsa -out dkim.key -traditional 1024
openssl rsa -in dkim.key -pubout -out dkim.pub.key

You will need the files dkim.key and dkim.pub.key for the next steps.

For email gurus, we have chosen 1024 key length instead of 2048 for DNS simplicity as some registrars don't play well with long TXT record.

DNS

Please note that DNS changes could take up to 24 hours to propagate. In practice, it's a lot faster though (~1 minute or so in our test). In DNS setup, we usually use domain with a trailing dot (.) at the end to force using absolute domain.

MX record

Create a MX record that points mydomain.com. to app.mydomain.com. with priority 10.

To verify if the DNS works, the following command

dig @1.1.1.1 mydomain.com mx

should return:

mydomain.com.	3600	IN	MX	10 app.mydomain.com.

A record

An A record that points app.mydomain.com. to your server IP. If you are using CloudFlare, we recommend to disable the "Proxy" option. To verify, the following command

dig @1.1.1.1 app.mydomain.com a

should return your server IP.

DKIM

Set up DKIM by adding a TXT record for dkim._domainkey.mydomain.com. with the following value:

v=DKIM1; k=rsa; p=PUBLIC_KEY

with PUBLIC_KEY being your dkim.pub.key but

• remove the -----BEGIN PUBLIC KEY----- and -----END PUBLIC KEY-----
• join all the lines on a single line.

For example, if your dkim.pub.key is

-----BEGIN PUBLIC KEY-----
ab
cd
ef
gh
-----END PUBLIC KEY-----

then the PUBLIC_KEY would be abcdefgh.

You can get the PUBLIC_KEY by running this command:

sed "s/-----BEGIN PUBLIC KEY-----/v=DKIM1; k=rsa; p=/g" $(pwd)/dkim.pub.key | sed 's/-----END PUBLIC KEY-----//g' |tr -d '\n' | awk 1

To verify, the following command

dig @1.1.1.1 dkim._domainkey.mydomain.com txt

should return the above value.

SPF

From Wikipedia https://en.wikipedia.org/wiki/Sender_Policy_Framework

Sender Policy Framework (SPF) is an email authentication method designed to detect forging sender addresses during the delivery of the email

Similar to DKIM, setting up SPF is highly recommended. Add a TXT record for mydomain.com. with the value:

v=spf1 mx ~all

What it means is only your server can send email with @mydomain.com domain. To verify, the following command

dig @1.1.1.1 mydomain.com txt

should return the above value.

DMARC

From Wikipedia https://en.wikipedia.org/wiki/DMARC

It (DMARC) is designed to give email domain owners the ability to protect their domain from unauthorized use, commonly known as email spoofing

Setting up DMARC is also recommended. Add a TXT record for _dmarc.mydomain.com. with the following value

v=DMARC1; p=quarantine; adkim=r; aspf=r

This is a relaxed DMARC policy. You can also use a more strict policy with v=DMARC1; p=reject; adkim=s; aspf=s value.

To verify, the following command

dig @1.1.1.1 _dmarc.mydomain.com txt

should return the set value.

For more information on DMARC, please consult https://tools.ietf.org/html/rfc7489

Docker

Now the boring DNS stuffs are done, let's do something more fun!

If you don't already have Docker installed on your server, please follow the steps on Docker CE for Ubuntu to install Docker.

You can also install Docker using the docker-install script which is

curl -fsSL https://get.docker.com | sh

Prepare the Docker network

This Docker network will be used by the other Docker containers run in the next steps. Later, we will setup Postfix to authorize this network.

sudo docker network create -d bridge \
    --subnet=10.0.0.0/24 \
    --gateway=10.0.0.1 \
    sl-network

Postgres

This section creates a Postgres database using Docker.

If you already have a Postgres database in use, you can skip this section and just copy the database configuration (i.e. host, port, username, password, database name) to use in the next sections.

Run a Postgres Docker container as your Postgres database server. Make sure to replace myuser and mypassword with something more secret.

docker run -d \
    --name sl-db \
    -e POSTGRES_PASSWORD=mypassword \
    -e POSTGRES_USER=myuser \
    -e POSTGRES_DB=simplelogin \
    -p 127.0.0.1:5432:5432 \
    -v $(pwd)/sl/db:/var/lib/postgresql/data \
    --restart always \
    --network="sl-network" \
    postgres:12.1

To test whether the database operates correctly or not, run the following command:

docker exec -it sl-db psql -U myuser simplelogin

you should be logged in the postgres console. Type exit to exit postgres console.

Postfix

Install postfix and postfix-pgsql. The latter is used to connect Postfix and the Postgres database in the next steps.

sudo apt-get install -y postfix postfix-pgsql -y

Choose "Internet Site" in Postfix installation window then keep using the proposed value as System mail name in the next window.

Replace /etc/postfix/main.cf with the following content. Make sure to replace mydomain.com by your domain.

# POSTFIX config file, adapted for SimpleLogin
smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
biff = no

# appending .domain is the MUA's job.
append_dot_mydomain = no

# Uncomment the next line to generate "delayed mail" warnings
#delay_warning_time = 4h

readme_directory = no

# See http://www.postfix.org/COMPATIBILITY_README.html -- default to 2 on
# fresh installs.
compatibility_level = 2

# TLS parameters
smtpd_tls_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file=/etc/ssl/private/ssl-cert-snakeoil.key
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
smtp_tls_security_level = may
smtpd_tls_security_level = may

# See /usr/share/doc/postfix/TLS_README.gz in the postfix-doc package for
# information on enabling SSL in the smtp client.

alias_maps = hash:/etc/aliases
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128 10.0.0.0/24

# Set your domain here
mydestination =
myhostname = app.mydomain.com
mydomain = mydomain.com
myorigin = mydomain.com

relay_domains = pgsql:/etc/postfix/pgsql-relay-domains.cf
transport_maps = pgsql:/etc/postfix/pgsql-transport-maps.cf

# HELO restrictions
smtpd_delay_reject = yes
smtpd_helo_required = yes
smtpd_helo_restrictions =
    permit_mynetworks,
    reject_non_fqdn_helo_hostnam