RainLoop+tomav/docker-mailserver: Cannot connect to server from RainLoop Webmail client

Question

To start off, I followed this guide to the letter: https://www.davd.eu/byecloud-building-a-mailserver-with-modern-webmail/

I am attempting to create a mailserver for my server, but I thought I'd test the above implementation locally first. Make sure I can get everything up and running at least so I can see what I should be expecting before trying it on the server. Here's what I did:

1. Added "127.0.0.1 mail.fancydomain.tld" to "/etc/hosts" (I wanted to start by using mail.fancydomain.tld rather than my actual domain that the mailserver will be on to minimize any changing while following the guide)

2. I created this "docker-compose.yml":

     version: "3" services: rainloop: image: hardware/rainloop links: - mail volumes: - ./data/rainloop:/rainloop/data mail: image: tvial/docker-mailserver:latest restart: always hostname: mail domainname: fancydomain.tld container_name: mail ports: - "25:25" - "143:143" - "587:587" - "993:993" - "4190:4190" volumes: - ./data/mail/data:/var/mail - ./data/mail/state:/var/mail-state - ./mail/config:/tmp/docker-mailserver/ - ./data/entry/acme/acme-v01.api.letsencrypt.org/sites/mail.fancydomain.tld:/tmp/ssl:ro environment: - ENABLE_SPAMASSASSIN=1 - ENABLE_CLAMAV=1 - ENABLE_FAIL2BAN=1 - ENABLE_POSTGREY=1 - ONE_DIR=1 - DMS_DEBUG=0 - ENABLE_MANAGESIEVE=1 cap_add: - NET_ADMIN entry: image: abiosoft/caddy:0.10.4 restart: always privileged: true links: - rainloop ports: - "80:80" - "443:443" volumes: - ./entry/Caddyfile:/etc/Caddyfile - ./data/entry:/root/.caddy 

   There is a small difference between this "docker-compose.yml" and the one provided by the site previously mentioned. All I did was remove the environment variables prefixed with "SSL_" as instructed by the guide for people who are just running it locally.

3. I created a directory in the current working directory called "entry" and created a "Caddyfile" with these contents:

     http://mail.fancydomain.tld { proxy / rainloop:8888 { transparent } } 

   Again, just a small difference from the one provided on the site. I prefixed the domain with "http://" for the same reason as step 2.

4. I successfully started the container with docker-compose up -d
5. I ran: curl -o setup.sh https://raw.githubusercontent.com/tomav/docker-mailserver/master/setup.sh; chmod a+x ./setup.sh curl -o setup.sh https://raw.githubusercontent.com/tomav/docker-mailserver/master/setup.sh; chmod a+x ./setup.sh to obtain the setup script.
6. I ran: ./setup.sh email add webmaster@fancydomain.tld fancypassword with those exact credentials, again to minimizes changes to keep track of.
7. I setup the DKIM records by running ./setup.sh config dkim but I did not proceed further with these records... As I'm not sure what to do with these locally.
8. I successfully connected to the RainLoop Webmail client via, " http://mail.fancydomain.tld/ " and proceeded to " http://mail.fancydomain.tld/?admin " to login with the credentials: Login=admin Password=12345

9. I proceeded to "Domains" > "Add Domain" and used filled out the form as so:

    Name: fancydomain.tld IMAP Server: mail Port: 143 Secure: STARTTLS SMTP Server: mail Port: 587 Secure: STARTTLS Use short login: Checked Use authentication: Checked SIEVE Allow sieve scripts: Checked Server: mail Port: 4190 Secure: STARTTLS 

10. From here I returned to " http://mail.fancydomain.tld " and tried to login to the Webmail client with this login: Login=webmaster@fancydomain.tld Password=fancypassword

This is where I get the error: "Can't connect to server"

I am not sure where to go from here. I don't know how to troubleshoot at all. Can I please get some help on what I should be doing to troubleshoot and figure out where the error is?

Thank you!

07/01/18 Update: So... I added "127.0.0.1 mail" into "/etc/hosts" and it worked! RainLoop can now connect to my mailserver! This brings up a new question though. For step 9, instead of "mail" for the three "Server" fields, I tried, "mail.fancydomain.tld" and according to the test, the connection is being refused. Why would the connection be refused for the full domain but not the short domain?

Answer 1

The solution for this one it to make sure both containers, RainLoop and Mail, share a bridged network. Then all the configurations can stay the same.