OPS345 Lab 7

• dovecot with imaps
• webmail

• can't use the same keys generated in www lab, they're for the wrong FQDN

andrew@p51:~/prog/seneca/ops345/new$ sudo su -
root@p51:~# certonly --manual --preferred-challenges dns
certonly: command not found
root@p51:~# certbot certonly --manual --preferred-challenges dns
Saving debug log to /var/log/letsencrypt/letsencrypt.log
Plugins selected: Authenticator manual, Installer None
Please enter in your domain name(s) (comma and/or space separated)  (Enter 'c'
to cancel): email.asmith15.ops345.ca
Obtaining a new certificate
Performing the following challenges:
dns-01 challenge for email.asmith15.ops345.ca

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NOTE: The IP of this machine will be publicly logged as having requested this
certificate. If you're running certbot in manual mode on a machine that is not
your server, please ensure you're okay with that.

Are you OK with your IP being logged?
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(Y)es/(N)o: y

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Please deploy a DNS TXT record under the name
_acme-challenge.email.asmith15.ops345.ca with the following value:

PdK1vlZnYMdBO7untofSCkfXH2ejk3EE019R7A90x7Q

Before continuing, verify the record is deployed.
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Press Enter to Continue
Waiting for verification...
Cleaning up challenges

IMPORTANT NOTES:
 - Congratulations! Your certificate and chain have been saved at:
   /etc/letsencrypt/live/email.asmith15.ops345.ca/fullchain.pem
   Your key file has been saved at:
   /etc/letsencrypt/live/email.asmith15.ops345.ca/privkey.pem
   Your cert will expire on 2022-02-28. To obtain a new or tweaked
   version of this certificate in the future, simply run certbot
   again. To non-interactively renew *all* of your certificates, run
   "certbot renew"
 - If you like Certbot, please consider supporting our work by:

   Donating to ISRG / Let's Encrypt:   https://letsencrypt.org/donate
   Donating to EFF:                    https://eff.org/donate-le

root@p51:~# cp /etc/letsencrypt/live/email.asmith15.ops345.ca/cert.pem ~andrew/prog/seneca/ops345/new/keys/email.asmith15.ops345.ca.cert.pem
root@p51:~# cp /etc/letsencrypt/live/email.asmith15.ops345.ca/privkey.pem ~andrew/prog/seneca/ops345/new/keys/email.asmith15.ops345.ca.key.pem
root@p51:~# chown andrew ~andrew/prog/seneca/ops345/new/keys/email.asmith15.ops345.ca.*

• Put keys on the email server:

scp -P 2212 -i keys/ssh/ops345-all-aws-machines.pem keys/email.asmith15.ops345.ca.* andrew@34.202.103.43:~
[root@email andrew]# cp email.asmith15.ops345.ca.cert.pem /etc/pki/tls/certs/
[root@email andrew]# cp email.asmith15.ops345.ca.key.pem /etc/pki/tls/private/

• configure postfix to enable encrypted connections from client software. add this to the bottom of main.cf:

# Settings to enable secure SMTP using my self-signed certificate:
smtpd_tls_auth_only = no
smtpd_use_tls = yes
smtp_use_tls = yes
smtpd_tls_key_file = /etc/pki/tls/private/email.asmith15.ops345.ca.key.pem
smtpd_tls_cert_file = /etc/pki/tls/certs/email.asmith15.ops345.ca.cert.pem
tls_random_source = dev:/dev/urandom
smtpd_tls_loglevel = 1

• test with telnet/EHLO: should say 250-STARTTLS
• complete test will be done with thunderbird later
• dovecot installed in previous lab, it needs very little configuration for our simple setup
• /etc/dovecot/dovecot.conf:
• Modify the protocols option so that Dovecot will work with IMAP connections, no POP3 or LMTP.
• 10-ssl.conf:

ssl_cert = </etc/pki/tls/certs/email.asmith15.ops345.ca.cert.pem
ssl_key = </etc/pki/tls/private/email.asmith15.ops345.ca.key.pem

• ss should show port 993, no 995 or 110
• there's no iptables running on email, so just open port 993 in ops345sgemail
• configure thunderbird:
  • IMAP: email.asmith15.ops345.ca, SSL 993, normal password, username without @domain
  • SMTP: email.asmith15.ops345.ca, STARTTLS 25, normal password, username without @domain
• tail -f /var/log/maillog and send a message from thunderbird
• The message is not sent, because postfix is not configured to authenticate users. encryption alone is not enough.
• https://www.xmodulo.com/enable-user-authentication-postfix-smtp-server-sasl.html
  • except the SSL/TLS parameters part.
• Send email again. Note the messages about connection timed out. We can't do anything about that in AWS Academy:
  • https://aws.amazon.com/premiumsupport/knowledge-center/ec2-port-25-throttle/
• There's more to do anyway to set up a real sending server, as a minimum DKIM/SPF but reverse DNS for the domain also helps.