Memindah Akaun & Email Server Lama ke Baru, SMTP relay & IMSS

Install standard desktop GNOME

Move or migrate user accounts to from old Linux server a new Linux

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How do I Move or migrate user accounts to from old Linux server a new Cent OS Linux server including mails? This new system a fresh installation.

A. You can migrate users from old Linux server to new Linux sever with standard commands such as tar, awk, scp and others. This is also useful if you are using old Linux distribution such as Redhat 9 or Debian 2.x.

Following files/dirs are required for traditional Linux user management:
* /etc/passwd - contains various pieces of information for each user account

* /etc/shadow - contains the encrypted password information for user’s accounts and optional the password aging information.

* /etc/group - defines the groups to which users belong

* /etc/gshadow - group shadow file (contains the encrypted password for group)

* /var/spool/mail - Generally user emails are stored here.

* /home - All Users data is stored here.

You need to backup all of the above files and directories from old server to new Linux server.

Commands to type on old Linux system

First create a tar ball of old uses (old Linux system). Create a directory:
# mkdir /root/move/
Setup UID filter limit:
# export UGIDLIMIT=500
Now copy /etc/passwd accounts to /root/move/passwd.mig using awk to filter out system account (i.e. only copy user accounts)
# awk -v LIMIT=$UGIDLIMIT -F: '($3>=LIMIT) && ($3!=65534)' /etc/passwd > /root/move/passwd.mig
Copy /etc/group file:
# awk -v LIMIT=$UGIDLIMIT -F: '($3>=LIMIT) && ($3!=65534)' /etc/group > /root/move/group.mig
Copy /etc/shadow file:
# awk -v LIMIT=$UGIDLIMIT -F: '($3>=LIMIT) && ($3!=65534) {print $1}' /etc/passwd | tee - |egrep -f - /etc/shadow > /root/move/shadow.mig
Copy /etc/gshadow (rarely used):
# cp /etc/gshadow /root/move/gshadow.mig
Make a backup of /home and /var/spool/mail dirs:
# tar -zcvpf /root/move/home.tar.gz /home
# tar -zcvpf /root/move/mail.tar.gz /var/spool/mail

Where,

· Users that are added to the Linux system always start with UID and GID values of as specified by Linux distribution or set by admin. Limits according to different Linux distro:

· RHEL/CentOS/Fedora Core : Default is 500 and upper limit is 65534 (/etc/libuser.conf).

· Debian and Ubuntu Linux : Default is 1000 and upper limit is 29999 (/etc/adduser.conf).

· You should never ever create any new system user accounts on the newly installed Cent OS Linux. So above awk command filter out UID according to Linux distro.

· export UGIDLIMIT=500 - setup UID start limit for normal user account. Set this value as per your Linux distro.

· awk -v LIMIT=$UGIDLIMIT -F: ‘($3>=LIMIT) && ($3!=65534)’ /etc/passwd > /root/move/passwd.mig - You need to pass UGIDLIMIT variable to awk using -v option (it assigns value of shell variable UGIDLIMIT to awk program variable LIMIT). Option -F: sets the field separator to : . Finally awk read each line from /etc/passwd, filter out system accounts and generates new file /root/move/passwd.mig. Same logic is applies to rest of awk command.

· tar -zcvpf /root/move/home.tar.gz /home - Make a backup of users /home dir

· tar -zcvpf /root/move/mail.tar.gz /var/spool/mail - Make a backup of users mail dir

Use scp or usb pen or tape to copy /root/move to a new Linux system.
# scp -r /root/move/* user@new.linuxserver.com:/path/to/location

Commands to type on new Linux system

First, make a backup of current users and passwords:
# mkdir /root/newsusers.bak
# cp /etc/passwd /etc/shadow /etc/group /etc/gshadow /root/newsusers.bak

Now restore passwd and other files in /etc/
# cd /path/to/location
# cat passwd.mig >> /etc/passwd
# cat group.mig >> /etc/group
# cat shadow.mig >> /etc/shadow
# /bin/cp gshadow.mig /etc/gshadow

Please note that you must use >> (append) and not > (create) shell redirection.

Now copy and extract home.tar.gz to new server /home
# cd /
# tar -zxvf /path/to/location/home.tar.gz

Now copy and extract mail.tar.gz (Mails) to new server /var/spool/mail
# cd /
# tar -zxvf /path/to/location/mail.tar.gz

Now reboot system; when the Linux comes back, your user accounts will work as they did before on old system:
# reboot

Please note that if you are new to Linux perform above commands in a sandbox environment. Above technique can be used to UNIX to UNIX OR UNIX to Linux account migration. You need to make couple of changes but overall the concept remains the same.

Stopping Spam with Sendmail

Email spam can be defined as unnecessary and unwanted email received by a user that probably does not know the sender and never requested the communication. It is a very disruptive, costly, and widespread abuse of Internet communication standards.
Sendmail has made it (relatively) easy to block new spamming techniques being employed to send junk email using your system. It even blocks many of the more usual spamming methods by default. You would need to consciously activate them by changing your /etc/mail/sendmail.mc file in a particular way to make your system susceptible.
For example, forwarding of SMTP messages, also referred to as SMTP relaying, has been disabled by default since Sendmail version 8.9. Before this change occurred, Sendmail would direct your mail host (x.org) to accept messages from one party (y.com) and send them to a different party (z.net). Now, however, you have to specifically tell Sendmail to permit a domain to relay mail through your domain. Simply edit the /etc/mail/relay-domains file and restart Sendmail by typing the service sendmail restart command as root to activate the changes.
However, many times, your users may be bombarded with spam from other servers throughout the Internet that are beyond your control. In these instances, you can use Sendmail's access control features available through the /etc/mail/access file. As root, add the domains that you would like to block or specifically allow access, such as:

badspammer.com       550 Go away and don't spam us anymore

tux.badspammer.com   OK

10.0                 RELAY

Figure 16-4. Example settings for access
Because /etc/mail/access is a database, you need to use makemap to activate your changes by recreating the database map. This is easily done by running the makemap hash /etc/mail/access < /etc/mail/access command as root.
This example shows that any email sent from badspammer.com would be blocked with a 550 RFC-821 compliant error code and message back to the spammer, except for email sent from the tux.badspammer.com sub-domain, which would be accepted. The last line shows that any email sent from the 10.0.*.* network can be relayed through your mail server.
As you might expect, this example only scratches the surface of what Sendmail can do in terms of allowing or blocking access. See the /usr/share/doc/sendmail/README.cf for more detailed information and examples.

Membaiki “yum update” yang gagal berfungsi.

Error Messsage :

---> Package perl-Compress-Raw-Bzip2.i386 0:2.021-1.el5.rf set to be updated
---> Package perl-Compress-Raw-Zlib.i386 0:2.021-1.el5.rf set to be updated
--> Processing Dependency: perl-Compress-Zlib for package:
solarspeed-openwebmail
--> Finished Dependency Resolution
solarspeed-openwebmail-2.52-SOL4AV.i386 from installed has depsolving
problems
--> Missing Dependency: perl-Compress-Zlib is needed by package
solarspeed-openwebmail-2.52-SOL4AV.i386 (installed)
Error: Missing Dependency: perl-Compress-Zlib is needed by package
solarspeed-openwebmail-2.52-SOL4AV.i386 (installed)
You could try using --skip-broken to work around the problem
You could try running: package-cleanup --problems
package-cleanup --dupes
rpm -Va --nofiles --nodigest

#cuba install guna “yum install perl-Compress-Zlib”

#Jika gagal cari fail RPM perl-Compress-Zlib dan install

#gunakan rpm –Uvh –nodeps ***** untuk upgrade pakej yang diperlukan perl-Compress-Zlib jika perlu.

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