In trying to follow the Ubuntu guide for postfix and mailman, I do not understand these directions:

This build of mailman runs as list. It must have permission to read /etc/aliases and read and write /var/lib/mailman/data/aliases. Do this with these commands:

sudo chown root:list /var/lib/mailman/data/aliases
sudo chown root:list /etc/aliases

Save and run:

sudo newaliases

I'm getting this kind of error:

root@dur:~# 
root@dur:~# 
root@dur:~# telnet localhost 25
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
220 dur.bounceme.net ESMTP Postfix (Ubuntu)
ehlo dur
250-dur.bounceme.net
250-PIPELINING
250-SIZE 10240000
250-VRFY
250-ETRN
250-STARTTLS
250-ENHANCEDSTATUSCODES
250-8BITMIME
250 DSN
quit
221 2.0.0 Bye
Connection closed by foreign host.
root@dur:~# 
root@dur:~# tail /var/log/mail.log
Aug 28 01:16:43 dur postfix/master[19444]: terminating on signal 15
Aug 28 01:16:43 dur postfix/postfix-script[19558]: starting the Postfix mail system
Aug 28 01:16:43 dur postfix/master[19559]: daemon started -- version 2.9.1, configuration /etc/postfix
Aug 28 01:16:45 dur postfix/postfix-script[19568]: stopping the Postfix mail system
Aug 28 01:16:45 dur postfix/master[19559]: terminating on signal 15
Aug 28 01:16:45 dur postfix/postfix-script[19673]: starting the Postfix mail system
Aug 28 01:16:45 dur postfix/master[19674]: daemon started -- version 2.9.1, configuration /etc/postfix
Aug 28 01:17:22 dur postfix/smtpd[19709]: error: open database /var/lib/mailman/data/aliases.db: No such file or directory
Aug 28 01:17:22 dur postfix/smtpd[19709]: connect from localhost[127.0.0.1]
Aug 28 01:18:37 dur postfix/smtpd[19709]: disconnect from localhost[127.0.0.1]
root@dur:~# 
root@dur:~# postconf -n
alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases, hash:/var/lib/mailman/data/aliases
append_dot_mydomain = no
biff = no
broken_sasl_auth_clients = yes
config_directory = /etc/postfix
default_transport = smtp
home_mailbox = Maildir/
inet_interfaces = loopback-only
mailbox_command = /usr/lib/dovecot/deliver -c /etc/dovecot/conf.d/01-mail-stack-delivery.conf -m "${EXTENSION}"
mailbox_size_limit = 0
mailman_destination_recipient_limit = 1
mydestination = dur, dur.bounceme.net, localhost.bounceme.net, localhost
myhostname = dur.bounceme.net
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
readme_directory = no
recipient_delimiter = +
relay_domains = lists.dur.bounceme.net
relay_transport = relay
relayhost =
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
smtp_use_tls = yes
smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
smtpd_recipient_restrictions = reject_unknown_sender_domain, reject_unknown_recipient_domain, reject_unauth_pipelining, permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination
smtpd_sasl_auth_enable = yes
smtpd_sasl_authenticated_header = yes
smtpd_sasl_local_domain = $myhostname
smtpd_sasl_path = private/dovecot-auth
smtpd_sasl_security_options = noanonymous
smtpd_sasl_type = dovecot
smtpd_tls_auth_only = yes
smtpd_tls_cert_file = /etc/ssl/certs/ssl-mail.pem
smtpd_tls_key_file = /etc/ssl/private/ssl-mail.key
smtpd_tls_mandatory_ciphers = medium
smtpd_tls_mandatory_protocols = SSLv3, TLSv1
smtpd_tls_received_header = yes
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtpd_use_tls = yes
tls_random_source = dev:/dev/urandom
transport_maps = hash:/etc/postfix/transport
root@dur:~# 
root@dur:~# 

And am wondering what connection might be. I do see that I don't have the requisite files:

root@dur:~# 
root@dur:~# ll /var/lib/mailman/data/aliases
ls: cannot access /var/lib/mailman/data/aliases: No such file or directory
root@dur:~# 

At what stage were those aliases created? How can I create them? Is that what's causing the error error: open database /var/lib/mailman/data/aliases.db: No such file or directory Aug 28 01:17:22 dur postfix/smtpd[19709]: connect from localhost[127.0.0.1]?