When using CentOS, you may find yourself requiring to use the "yum" package manager, when you do not have Internet access, or your link to download packages is to slow.

If you have the CentOS DVD/CD available you can mount the disk locally and install packages via yum.

This is helpful to speed up the yum process and install packages locally.

# mkdir /media/CentOS
# mount /dev/cdrom /media/CentOS
# yum --disablerepo=* --enablerepo=c5-media install [package]

Replace c5-media with c4-media if using CentOS 4.

Examples, install all php* packages and mysql* using the local CD

# yum --disablerepo=* --enablerepo=c5-media install php-*
# yum --disablerepo=* --enablerepo=c5-media install mysql*

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Using yum is great, since it will automatically satisfy dependencies and install packages in full. Much easier then manually running rpm!

You may want to enable ETRN for selected hosts, so that messages destined for them can be retrieved in case the destination server goes down. To enable ETRN, do the following:

- open up /usr/local/atmail/mailserver/configure

- find:

acl_smtp_data = acl_check_content

- below it, add:

acl_smtp_etrn = accept

- then, find:

begin acl

- below it, add:

acl_smtp_etrn:
 accept hosts = +relay_from_hosts

- save changes, restart Exim.

To test if it's working, do the following (preferably from an IP address in your Mail Relay tables):

- telnet to SMTP:

% telnet [hostname] 25

*(Replace [hostname] with the hostname/IP of the server running @Mail)

- you will then get the greeting. Do a mock ehlo (see line in bold):

Connected to localhost.localdomain (127.0.0.1).
Escape character is '^]'.
220 foo.com Welcome to the @Mail SMTP Server ( Exim )
ehlo [your hostname] 
250-hermes.calacode.com Hello localhost [127.0.0.1]
250-SIZE 52428800
250-ETRN
250-PIPELINING
250-AUTH LOGIN
250 HELP

*(Replace [your hostname] with your hostname)

- verify that it works by executing:

ETRN #[domain name]

*(Replace [domain name] with the domain name you want to retrieve emails for)