Simple and full-featured mail server as a set of multiple docker images includes :
- Postfix : a full set smtp email server
- Dovecot : secure imap and pop3 email server
- Rspamd : anti-spam filter with SPF, DKIM, DMARC, ARC, ratelimit and greylisting capabilities
- Clamav : antivirus with automatic updates and third-party signature databases
- Zeyple : automatic GPG encryption of all your e-mails
- Sieve : email filtering (vacation auto-responder, auto-forward...etc)
- Fetchmail : fetch e-mails from external IMAP/POP3 server into local mailbox
- Rainloop : web based email client
- Postfixadmin : web based administration interface
- Unbound: recursive caching DNS resolver with DNSSEC support
- NSD : authoritative DNS server with DNSSEC support
- Træfik : modern HTTP reverse proxy
- SSL : lets encrypt with auto-renewal, custom and self-signed certificates support
- Supporting multiple virtual domains over MySQL backend
- Integration tests with Travis CI
- Automated builds on DockerHub
- System Requirements
- Prerequisites
- Installation
- Environment variables
- SSL certificates
- GPG encryption
- Relaying from other networks
- Third-party clamav signature databases
- DNS resolver
- Persistent files and folders
- Override postfix configuration
- Override dovecot configuration
- Ansible Playbooks
- Community projects
- Useful Thunderbird extensions
- Donation
Please check, if your system meets the following minimum requirements :
Type | Without ClamAV | With ClamAV |
---|---|---|
CPU | 1 GHz | 1 GHz |
RAM | 1.5 GiB | 2 GiB |
Type | Without ClamAV | With ClamAV |
---|---|---|
CPU | 1 GHz | 1 GHz |
RAM | 512 MiB | 1 GiB |
Please remove any web server and mail services running on your server. I recommend using a clean installation of your prefered distro. If you are using Debian, remember to remove the default MTA Exim4 :
# apt-get purge exim4*
Also make sure that no other application is interfering with mail server configuration :
# netstat -tulpn | grep -E -w '25|80|110|143|443|465|587|993|995|4190'
If this command returns any results please remove or stop the application running on that port.
If you have a firewall, unblock the following ports, according to your needs :
Service | Software | Protocol | Port |
---|---|---|---|
SMTP | Postfix | TCP | 25 |
HTTP | Nginx | TCP | 80 |
POP3 | Dovecot | TCP | 110 |
IMAP | Dovecot | TCP | 143 |
HTTPS | Nginx | TCP | 443 |
SMTPS | Postfix | TCP | 465 |
Submission | Postfix | TCP | 587 |
IMAPS | Dovecot | TCP | 993 |
POP3S | Dovecot | TCP | 995 |
ManageSieve | Dovecot | TCP | 4190 |
I recommend you to use hardware/nsd-dnssec as an authoritative name server with DNSSEC capabilities. NSD is an authoritative only, high performance, simple and open source name server.
A correct DNS setup is required, this step is very important.
HOSTNAME | CLASS | TYPE | PRIORITY | VALUE |
---|---|---|---|---|
IN | A/AAAA | any | 1.2.3.4 | |
spam | IN | CNAME | any | mail.domain.tld. |
webmail | IN | CNAME | any | mail.domain.tld. |
postfixadmin | IN | CNAME | any | mail.domain.tld. |
@ | IN | MX | 10 | mail.domain.tld. |
@ | IN | TXT | any | "v=spf1 a mx ip4:SERVER_IPV4 ~all" |
mail._domainkey | IN | TXT | any | "v=DKIM1; k=rsa; p=YOUR DKIM Public Key" |
_dmarc | IN | TXT | any | "v=DMARC1; p=reject; rua=mailto:postmaster@domain.tld; ruf=mailto:admin@domain.tld; fo=0; adkim=s; aspf=s; pct=100; rf=afrf; sp=reject" |
Notes:
- Make sure that the PTR record of your IP matches the FQDN (default : mail.domain.tld) of your mailserver host. This record is usually set in your web hosting interface.
- DKIM, SPF and DMARC records are recommended to build a good reputation score.
- The DKIM public key will be available on host after the container startup :
/mnt/docker/mail/dkim/domain.tld/public.key
To regenerate your public and private keys, remove the /mnt/docker/mail/dkim/domain.tld
folder. By default a 1024-bit key is generated, you can increase this size by setting the OPENDKIM_KEY_LENGTH
environment variable with a higher value. Check your domain registrar support to verify that it supports a TXT record long enough for a key larger than 1024 bits.
These DNS record will raise your trust reputation score and reduce abuse of your domain name. You can find more information here :
You can audit your mailserver with the following assessment services :
💡 The reverse proxy used in this setup is Traefik, but you can use the solution of your choice (Nginx, Apache, Haproxy, Caddy, H2O...etc).
# Create a new docker network for Traefik
docker network create http_network
# Create the required folders and files
mkdir -p /mnt/docker/traefik/acme && cd /mnt/docker \
&& curl https://raw.githubusercontent.com/hardware/mailserver/master/docker-compose.sample.yml -o docker-compose.yml \
&& curl https://raw.githubusercontent.com/hardware/mailserver/master/sample.env -o .env \
&& curl https://raw.githubusercontent.com/hardware/mailserver/master/traefik.sample.toml -o traefik/traefik.toml \
&& touch traefik/acme/acme.json \
&& chmod 600 docker-compose.yml .env traefik/traefik.toml traefik/acme/acme.json
Edit the .env
and traefik.toml
, adapt to your needs, then start all services :
docker-compose up -d
PostfixAdmin is a web based interface used to manage mailboxes, virtual domains and aliases.
- Docker image : https://github.com/hardware/postfixadmin
- How to setup : Postfixadmin initial configuration
Rainloop is a simple, modern and fast webmail with Sieve scripts support (filters and vacation message), GPG and a modern user interface.
- Docker image : https://github.com/hardware/rainloop
- How to setup : Rainloop initial configuration
At first launch, the container takes few minutes to generate SSL certificates (if needed), DKIM keypair and update clamav database, all of this takes some time (1/2 minutes). This image comes with a snake-oil self-signed certificate, please use your own trusted certificates. See below for configuration.
List of webservices available:
Service | URI |
---|---|
Traefik dashboard | https://mail.domain.tld/ |
Rspamd dashboard | https://spam.domain.tld/ |
Administration | https://postfixadmin.domain.tld/ |
Webmail | https://webmail.domain.tld/ |
Traefik dashboard use a basic authentication (user:admin, password:12345), the password can be encoded in MD5, SHA1 and BCrypt. You can use htpasswd to generate those ones. Users can be specified directly in the traefik.toml
file. Rspamd dashboard use the password defined in your docker-compose.yml
.
You can check the startup logs with this command :
# docker logs -f mailserver
[INFO] Let's encrypt live directory found
[INFO] Using /etc/letsencrypt/live/mail.domain.tld folder
[INFO] Creating DKIM keys for domain domain.tld
[INFO] Database hostname found in /etc/hosts
[INFO] Fetchmail forwarding is enabled.
[INFO] Automatic GPG encryption is enabled.
[INFO] ManageSieve protocol is enabled.
[INFO] POP3 protocol is enabled.
-------------------------------------------------------------------------------------
2017-08-26T11:06:58.885562+00:00 mail root: s6-supervise : spawning clamd process
2017-08-26T11:06:59.059077+00:00 mail root: s6-supervise : spawning freshclam process
2017-08-26T11:06:59.395214+00:00 mail root: s6-supervise : spawning rspamd process
2017-08-26T11:07:01.615597+00:00 mail root: s6-supervise : spawning unbound process
2017-08-26T11:07:01.870856+00:00 mail root: s6-supervise : spawning postfix process
2017-08-26T11:07:03.303536+00:00 mail root: s6-supervise : spawning dovecot process
...
If you use Ansible, I recommend you to go to see @ksylvan playbooks here : https://github.com/ksylvan/docker-mail-server
Variable | Description | Type | Default value |
---|---|---|---|
VMAILUID | vmail user id | optional | 1024 |
VMAILGID | vmail group id | optional | 1024 |
VMAIL_SUBDIR | Individual mailbox' subdirectory | optional | |
OPENDKIM_KEY_LENGTH | Size of your DKIM RSA key pair | optional | 1024 |
PASSWORD_SCHEME | Passwords encryption scheme | optional | SHA512-CRYPT |
DBHOST | MariaDB instance ip/hostname | optional | mariadb |
DBPORT | MariaDB instance port | optional | 3306 |
DBUSER | MariaDB database username | optional | postfix |
DBNAME | MariaDB database name | optional | postfix |
DBPASS | MariaDB database password or location of a file containing it | required | null |
REDIS_HOST | Redis instance ip/hostname | optional | redis |
REDIS_PORT | Redis instance port | optional | 6379 |
REDIS_PASS | Redis database password or location of a file containing it | optional | null |
REDIS_NUMB | Redis database number | optional | 0 |
RSPAMD_PASSWORD | Rspamd WebUI and controller password or location of a file containing it | required | null |
ADD_DOMAINS | Add additional domains to the mailserver separated by commas (needed for dkim keys etc.) | optional | null |
RELAY_NETWORKS | Additional IPs or networks the mailserver relays without authentication | optional | null |
DISABLE_RSPAMD_MODULE | List of disabled modules separated by commas | optional | null |
DISABLE_CLAMAV | Disable virus scanning | optional | false |
DISABLE_SIEVE | Disable ManageSieve protocol | optional | false |
DISABLE_SIGNING | Disable DKIM/ARC signing | optional | false |
DISABLE_GREYLISTING | Disable greylisting policy | optional | false |
DISABLE_RATELIMITING | Disable ratelimiting policy | optional | false |
DISABLE_DNS_RESOLVER | Disable the local DNS resolver | optional | false |
ENABLE_POP3 | Enable POP3 protocol | optional | false |
ENABLE_FETCHMAIL | Enable fetchmail forwarding | optional | false |
ENABLE_ENCRYPTION | Enable automatic GPG encryption | optional | false |
FETCHMAIL_INTERVAL | Fetchmail polling interval | optional | 10 |
RECIPIENT_DELIMITER | RFC 5233 subaddress extension separator (single character only) | optional | + |
- VMAIL_SUBDIR is the mail location subdirectory name
/var/mail/vhosts/%domain/%user/$subdir
. For more information, read this : https://wiki.dovecot.org/VirtualUsers/Home - PASSWORD_SCHEME for compatible schemes, read this : https://wiki.dovecot.org/Authentication/PasswordSchemes
- Currently, only a single RECIPIENT_DELIMITER is supported. Support for multiple delimiters will arrive with Dovecot v2.3.
- FETCHMAIL_INTERVAL must be a number between 1 and 59 minutes.
- Use DISABLE_DNS_RESOLVER if you have some DNS troubles and DNSSEC lookup issues with the local DNS resolver.
- Use DISABLE_RSPAMD_MODULE to disable any module listed here : https://rspamd.com/doc/modules/
Zeyple catches email from the postfix queue, then encrypts it if a corresponding recipient's GPG public key is found. Finally, it puts it back into the queue.
❗ Please enable this option carefully and only if you know what you are doing.
Switch ENABLE_ENCRYPTION
environment variable to true
. The public keyring will be saved in /var/mail/zeyple/keys
.
Please don't change the default value of RECIPIENT_DELIMITER
(default = "+"). If encryption is enabled with another delimiter, Zeyple could have an unpredictable behavior.
docker exec -ti mailserver encryption.sh import-key YOUR_KEY_ID
This command browses all /var/mail/vhosts/*
domains directories and users subdirectories to find all the recipients addresses in the mailserver.
docker exec -ti mailserver encryption.sh import-all-keys
docker exec -ti mailserver encryption.sh import-key YOUR_KEY_ID hkp://pgp.mit.edu
docker exec -ti mailserver encryption.sh import-all-keys hkp://keys.gnupg.net
You can use all options of gpg command line except an already assigned parameter called --homedir
.
docker exec -ti mailserver encryption.sh --list-keys
docker exec -ti mailserver encryption.sh --fingerprint
docker exec -ti mailserver encryption.sh --refresh-keys
docker exec -ti mailserver encryption.sh ...
Documentation : https://www.gnupg.org/documentation/manuals/gnupg/Operational-GPG-Commands.html
The RELAY_NETWORKS is a space separated list of additional IP addresses and subnets (in CIDR notation) which the mailserver relays without authentication. Hostnames are possible, but generally disadvised. IPv6 addresses must be surrounded by square brackets. You can also specify an absolut path to a file with IPs and networks so you can keep it on a mounted volume. Note that the file is not monitored for changes.
You can use this variable to allow other local containers to relay via the mailserver. Typically you would set this to the IP range of the default docker bridge (172.17.0.0/16) or the default network of your compose. If you are unable to determine, you might just add all RFC 1918 addresses 192.168.0.0/16 172.16.0.0/12 10.0.0.0/8
0.0.0.0/0
will turn your mailserver into an open relay!
To use Let's Encrypt certificates generated by Traefik, mount a new docker volume like this :
mailserver:
image: hardware/mailserver
volumes:
- /mnt/docker/traefik/acme:/etc/letsencrypt/acme
...
The startup script read the acme.json
file generated by Traefik and split into pem files all appropriate certificates (CN = mail.domain.tld).
docker logs -f mailserver
[INFO] Search for SSL certificates generated by Traefik
[INFO] acme.json found, dumping into pem files
[INFO] Let's encrypt live directory found
[INFO] Using /etc/letsencrypt/live/mail.domain.tld folder
Don't forget to add a new traefik frontend rule somewhere in your docker-compose.yml to generate a certificate for your mailserver FQDN (default : mail.domain.tld) subdomain.
# docker-compose.yml
labels:
- traefik.frontend.rule=Host:mail.${DOMAIN}
Alternatively, you can specify your domains in the traefik.toml
:
[acme]
onHostRule = false
[[acme.domains]]
main = "domain.tld"
sans = ["mail.domain.tld", "spam.domain.tld", "postfixadmin.domain.tld", "webmail.domain.tld"]
If the startup script does not find the appropriate SSL certificate and private key, look at Traefik's logs to see what's going on.
docker logs -f mailserver
[INFO] Search for SSL certificates generated by Traefik
[INFO] ...
[INFO] ...
[INFO] acme.json found, dumping into pem files
[ERROR] The certificate for mail.domain.tld or the private key was not found !"
[INFO] Don't forget to add a new traefik frontend rule to generate a certificate for mail.domain.tld subdomain"
[INFO] Look /mnt/docker/traefik/acme/dump.log and 'docker logs traefik' for more information"
# traefik.toml
[acme]
acmeLogging = true
docker-compose restart traefik && docker logs -f traefik
You can use Let's Encrypt or any other certification authority. Setup your docker-compose.yml
like this :
mailserver:
image: hardware/mailserver
volumes:
- /mnt/docker/ssl:/etc/letsencrypt
...
Request your certificates in /mnt/docker/ssl/live/mail.domain.tld
with an ACME client if you use Let's Encrypt, otherwise get your SSL certificates with the method provided by your CA and put everything needed in this directory.
Required files in this folder :
💡 If you only have the fullchain.pem and privkey.pem, the startup script extract automatically the cert.pem and chain.pem from fullchain.pem.
Filename | Description |
---|---|
privkey.pem | Private key for the certificate |
cert.pem | Server certificate only |
chain.pem | Root and intermediate certificates only, excluding server certificate |
fullchain.pem | All certificates, including server certificate. This is concatenation of cert.pem and chain.pem |
Example with acme.sh :
acme.sh --install-cert -d example.com \
--ca-file ${VOLUMES_ROOT_PATH}/ssl/live/mail.domain.tld/chain.pem \
--cert-file ${VOLUMES_ROOT_PATH}/ssl/live/mail.domain.tld/cert.pem \
--key-file ${VOLUMES_ROOT_PATH}/ssl/live/mail.domain.tld/privkey.pem \
--fullchain-file ${VOLUMES_ROOT_PATH}/ssl/live/mail.domain.tld/fullchain.pem \
--reloadcmd "docker restart mailserver"
Notes :
-
Important : When renewing certificates, you must restart the mailserver container.
-
If you do not use your own trusted certificates or those generated by Traefik, a default self-signed certificate (RSA 4096 bits SHA2) is added here :
/mnt/docker/mail/ssl/selfsigned/{cert.pem, privkey.pem}
. -
If you have generated a ECDSA certificate with a curve other than
prime256v1
(NIST P-256), you need to change the Postfix TLS configuration because of a change in OpenSSL >= 1.1.0. For example, if you usesecp384r1
elliptic curve with your ECDSA certificate, change thetls_eecdh_strong_curve
value :
# /mnt/docker/mail/postfix/custom.conf
tls_eecdh_strong_curve = secp384r1
Additional informations about this issue :
# IMAP STARTTLS - 143 port (IMAP)
openssl s_client -connect mail.domain.tld:143 -starttls imap -tlsextdebug
# SMTP STARTTLS - 587 port (Submission)
openssl s_client -connect mail.domain.tld:587 -starttls smtp -tlsextdebug
# IMAP SSL/TLS - 993 port (IMAPS)
openssl s_client -connect mail.domain.tld:993 -tlsextdebug
Clamav-unofficial-sigs provides a simple way to download and update third-party signature databases provided by Sanesecurity, FOXHOLE, OITC, Scamnailer, BOFHLAND, CRDF, Porcupine, Securiteinfo, MalwarePatrol, Yara-Rules Project, etc.
Readme : https://github.com/extremeshok/clamav-unofficial-sigs
Software | Protocol | Port |
---|---|---|
Rsync | TCP | 873 |
Curl | TCP | 443 |
Create your user.conf
file under /mnt/docker/mail/clamav-unofficial-sigs
directory to configure clamav-unofficial-sigs updater. This file override the default configuration specified in os.conf and master.conf. Don't forget, once you have completed the configuration of this file, set the value of user_configuration_complete
to yes
otherwise the script will not be able to execute.
# /mnt/docker/mail/clamav-unofficial-sigs/user.conf
# =========================
# MalwarePatrol : https://www.malwarepatrol.net
# MalwarePatrol 2016 (free) clamav signatures
#
# 1. Sign up for an account : https://www.malwarepatrol.net/signup-free.shtml
# 2. You will receive an email containing your password/receipt number
# 3. Login to your account at malwarePatrol
# 4. In My Accountpage, choose the ClamAV list you will download. Free subscribers only get ClamAV Basic, commercial subscribers have access to ClamAV Extended. Do not use the agressive lists.
# 5. In the download URL, you will see 3 parameters: receipt, product and list, enter them in the variables below.
# malwarepatrol_receipt_code="YOUR-RECEIPT-NUMBER"
# malwarepatrol_product_code="8"
# malwarepatrol_list="clamav_basic"
# malwarepatrol_free="yes"
# =========================
# SecuriteInfo : https://www.SecuriteInfo.com
# SecuriteInfo 2015 free clamav signatures
#
# Usage of SecuriteInfo 2015 free clamav signatures : https://www.securiteinfo.com
# - 1. Sign up for a free account : https://www.securiteinfo.com/clients/customers/signup
# - 2. You will receive an email to activate your account and then a followup email with your login name
# - 3. Login and navigate to your customer account : https://www.securiteinfo.com/clients/customers/account
# - 4. Click on the Setup tab
# - 5. You will need to get your unique identifier from one of the download links, they are individual for every user
# - 5.1. The 128 character string is after the http://www.securiteinfo.com/get/signatures/
# - 5.2. Example https://www.securiteinfo.com/get/signatures/your_unique_and_very_long_random_string_of_characters/securiteinfo.hdb
# Your 128 character authorisation signature would be : your_unique_and_very_long_random_string_of_characters
# - 6. Enter the authorisation signature into the config securiteinfo_authorisation_signature: replacing YOUR-SIGNATURE-NUMBER with your authorisation signature from the link
# securiteinfo_authorisation_signature="YOUR-SIGNATURE-NUMBER"
# After you have completed the configuration of this file, set the value to "yes"
user_configuration_complete="yes"
If the startup script detects this file, clamav-unofficial-sigs is automatically enabled and third-party databases downloaded under /mnt/docker/mail/clamav
after clamav startup. Once the databases are downloaded, a SIGHUP signal is sent to clamav to load the received signatures :
docker logs -f mailserver
[INFO] clamav-unofficial-sigs is enabled (user configuration found)
[...]
s6-supervise : clamav unofficial signature update running
s6-supervise : virus database downloaded, spawning clamd process
[...]
clamd[xxxxxx]: SIGHUP caught: re-opening log file.
s6-supervise : clamav unofficial signature update done
Unbound is a validating, recursive, and caching DNS resolver inside the container, you can control it with the remote server control utility.
Some examples :
# Display server status
docker exec -ti mailserver unbound-control status
# Print server statistics
docker exec -ti mailserver unbound-control stats_noreset
# Reload the server. This flushes the cache and reads the config file.
docker exec -ti mailserver unbound-control reload
Documentation : https://www.unbound.net/documentation/unbound-control.html
/mnt/docker
└──mail
├──postfix
| custom.conf
| ├──spool (Postfix queues directory)
│ │ defer
│ │ flush
│ │ hold
│ │ maildrop
│ │ ...
├──dovecot
| instances
| ssl-parameters.dat
| ├──conf.d (Custom dovecot configuration)
├──clamav (ClamAV databases directory)
│ bytecode.cvd
│ daily.cld
│ main.cvd
├──clamav-unofficial-sigs
│ user.conf
├──rspamd (Rspamd databases directory)
│ rspamd.rrd
| stats.ucl
├──zeyple
│ ├──keys (GPG public keyring)
│ │ pubring.kbx
│ │ trustdb.gpg
│ │ ...
├──sieve
│ default.sieve
│ custom.sieve (custom default sieve rules for all users)
├──dkim
│ ├──domain.tld
│ │ private.key
│ │ public.key
├──ssl
│ ├──selfsigned (Auto-generated if no certificate found)
│ │ cert.pem
│ │ privkey.pem
├──vhosts
│ ├──domain.tld
│ │ ├──user
│ │ │ .dovecot.sieve -> sieve/rainloop.user.sieve
│ │ │ .dovecot.svbin
│ │ │ ├──mail
│ │ │ │ ├──.Archive
│ │ │ │ ├──.Drafts
│ │ │ │ ├──.Sent
│ │ │ │ ├──.Spam
│ │ │ │ ├──.Trash
│ │ │ │ ├──cur
│ │ │ │ ├──new
│ │ │ │ ...
│ │ │ ├──sieve
│ │ │ │ rainloop.user.sieve (if using rainloop webmail)
Postfix default configuration can be overrided providing a custom configuration file at postfix format. This can be used to also add configuration that are not in default configuration. Postfix documentation remains the best place to find configuration options.
Each line in the provided file will be loaded into Postfix. Create a new file here /mnt/docker/mail/postfix/custom.conf
and add your custom options inside.
Example :
# /mnt/docker/mail/postfix/custom.conf
smtpd_banner = $myhostname ESMTP MyGreatMailServer
inet_protocols = ipv4
delay_notice_recipient = admin@domain.tld
delay_warning_time = 2h
docker logs -f mailserver
[INFO] Override : smtpd_banner = $myhostname ESMTP MyGreatMailServer
[INFO] Override : inet_protocols = ipv4
[INFO] Override : delay_notice_recipient = postmaster@domain.tld
[INFO] Override : delay_warning_time = 2h
[INFO] Custom Postfix configuration file loaded
Sometimes you might want to add additional configuration parameters or override the default ones. You can do so by placing configuration files to the persistent folder /mnt/docker/mail/dovecot/conf.d
.
Example:
# /mnt/docker/mail/dovecot/conf.d/20-imap.conf
protocol imap {
mail_max_userip_connections = 100
}
# /mnt/docker/mail/dovecot/conf.d/90-quota.conf
plugin {
quota_rule2 = Trash:storage=+200M
quota_exceeded_message = You have exceeded your mailbox quota.
}
- IMAP/SMTP username : user@domain.tld
- Incoming IMAP server : mail.domain.tld (your FQDN)
- Outgoing SMTP server : mail.domain.tld (your FQDN)
- IMAP port : 993
- SMTP port : 587
- IMAP Encryption protocol : SSL/TLS
- SMTP Encryption protocol : STARTTLS
- Postfix 3.1.6
- Dovecot 2.2.27
- Rspamd 1.6.6
- Fetchmail 6.3.26
- ClamAV 0.99.2
- Clamav Unofficial Sigs 5.6.2
- Zeyple 1.2.2
- Unbound 1.6.0
- s6 2.7.0.0
- Rsyslog 8.24.0
- ManageSieve server
- ksylvan/docker-mail-server : Ansible playbooks to easily deploy hardware/mailserver.
- rubentrancoso/mailserver-quicksetup : Automatic hardware/mailserver deployment on a digitalocean droplet.
- https://www.enigmail.net/
- https://github.com/moisseev/rspamd-spamness
- https://github.com/lieser/dkim_verifier
My Bitcoin address : 1LwRr6jvzPHnZsxjk6u3wcfP555ZeC47Tg
This address is signed cryptographically to prove that it belongs to me. https://keybase.io/hardware