====== Training per sysadmin ======

===== Verifica raggiungibilità host =====

Prima di tutto si deve verificare se si raggiunge il sistema remoto. 
Si può fare con il programma `ping <nome host o indirizzo IP>`

Il ping può essere utile per verificare anche la latenza di rete


===== Verifica raggiungibilità di un servizio =====


==== Esempio HTTP ====

TODO Costin

==== Esempio SSH ====

TODO Costin

==== Esempio SMTP (invio email) ====

TODO Costin


===== SMTP (avanzato) =====

Da non leggere se non si è già amministratori di un server email.

==== SMTP configuration ====

In order to have a working SMTP server we have to take care of "some" ;) points:

  * PTR reverse DNS record: ''dig +short ptr <reverse IP>.in-addr.arpa'' must give an hostname which DNS A record points to the <IP address> of your server.
  * DNS:
    * MX -> who exchange the mail for the domain?
    * SPF -> which addresses can be originated from the MX?
    * DKIM -> how are signed messages outgoing from the MX?
    * DMARC -> what actions do you suggest to mail receivers' providers regarding the conf of SPF/DKIM and where you would like to receive reports from them to tune your mail settings?

  * Furthermore we need working antispam and antivirus
  * And of course SMTP server only relay local or TLS + authenticated connections
  * Need to add DNS entries to the host that receives DMARC reports if domain is different from the one of the DMARC itself

=== References ===

  * https://wiki.zimbra.com/wiki/Best_Practices_on_Email_Protection:_SPF,_DKIM_and_DMARC
  * https://workaround.org/ispmail/jessie
  * https://workaround.org/ispmail/wheezy/smtpd-restrictions-spf-dkim-and-greylisting
  * DKIM on STMP RELAY server (trust hosts...) http://www.stevejenkins.com/blog/2011/08/installing-opendkim-rpm-via-yum-with-postfix-or-sendmail-for-rhel-centos-fedora/

  * Very useful thread for MS hotmail and outlook problems https://www.hmailserver.com/forum/viewtopic.php?t=27930
  * 
=== SMTP/IMAPs tests ===

  * Fantastic and happy! http://www.mail-tester.com/web-us64b
  * MX Toolbox non ha bisogno di presentazioni, molti test: https://mxtoolbox.com/
  * Documentazione DNS MailCow: https://mailcow.github.io/mailcow-dockerized-docs/prerequisite-dns/
  * SPF: http://tools.wordtothewise.com/spf/check/
  * SPF, DKIM, Antispam: http://dkimvalidator.com send an email to the given address and view results
  * DMARC: https://dmarcian.com/
  * IMAPs: http://wiki.dovecot.org/TestInstallation
  * SMTP: https://www.ndchost.com/wiki/mail/test-smtp-auth-telnet
  * SMTPs: https://www.saotn.org/tls-test-smtp-auth-plain-authentication-and-verify-starttls-connections/

==== Migrazione di un sistema di posta con soli alias verso Mailcow ====

  - [X] Backup e aggiornamento Mailcow
  - [X] Configurazione Mailcow -> aggiungere dominio
  - [X] Creare un utente admin specifico per il dominio
  - [X] Trasferire alias (copia da ''/etc/postfix/virtual_pdp'')
  - [X] Visualizzare tutte le impostazioni necessarie del DNS e si aggiornano i record DNS
  - [X] Effettuare il test: tra tutti mail-tester e mxtoolbox

=== Backup e aggiornamento ===

  cd /opt/mailcow-dockerized
  helper-scripts/backup_and_restore.sh backup all
  ./upgrade.sh
  ./upgrade.sh
  
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