IMAP is a very usefully protocol, but it lacks encryption. The dovecot package distributed with RHEL includes the ability to use IMAP over SSL, This requires the creation of a PEM format certificate.

cd /usr/share/ssl/certs

make dovecot.pem : Which generates the dovecot.pem certificate by reading MakeFile

Enable the imaps protocol from /etc/dovecot.conf

vi /etc/dovecot.conf

protocols = imap imaps

service dovecot restart : Restart the Dovecot service

Do the following steps as:

1. vi /etc/security/access.conf

-:john:LOCAL

2. vi /etc/pam.d/system-auth

account required /lib/security/pam_access.so

/etc/security/access.conf file helps to allow or deny login to users on the basis of origin.

Syntax of /etc/security/access.conf

permission : users : origins

The first field should be a "+" (access granted) or "-" (access denied) character.

The second field should be a list of one or more login names, group names, or ALL (always matches). A pattern of the form user@host is matched when the login name matches the "user" part, and when the "host" part matches the local machine name.

The third field should be a list of one or more tty names (for non-networked logins), host names, domain names (begin with "."), host addresses, internet network numbers (end with "."), ALL (always matches) or LOCAL (matches any string that does not contain a "." character).

In our example denied to john user to login locally.

Do the following steps as:

1. vi /etc/security/access.conf

-:jack:ALL EXCEPT station10.example.com

2. vi /etc/pam.d/system-auth

account required /lib/security/pam_access.so

/etc/security/access.conf file helps to allow or deny login to users on the basis of origin.

Syntax of /etc/security/access.conf

permission : users : origins

The first field should be a "+" (access granted) or "-" (access denied) character.

The second field should be a list of one or more login names, group names, or ALL (always matches). A pattern of the form user@host is matched when the login name matches the "user" part, and when the "host" part matches the local machine name.

The third field should be a list of one or more tty names (for non-networked logins), host names, domain names (begin with "."), host addresses, internet network numbers (end with "."), ALL (always matches) or LOCAL (matches any string that does not contain a "." character).

The EXCEPT operator makes it possible to write very compact rules

Do the following steps as:

1. vi /etc/samba/smb.conf

[global]

netbios name=station?

workgroup = mygroup

server string=Share from Linux Server

security=user

smb passwd file=/etc/samba/smbpasswd

encrypt passwords=yes

hosts allow=192.168.0.

[data]

path=/data

writable=yes

public=no

browsable=yes

2. service smb start| restart

3. chkconfig smb on

Samba servers helps to share the data between linux and windows. Configuration file is /etc/samba/smb.conf. There are some pre-defined section, i. global  use to define the global options, ii. Printers  use to share the printers, iii. homes  use to share the user’s home directory.

Security=user  validation by samba username and password. May be there are other users also. To allow certain share to certain user we should use valid users option.

smbpasswd  Helps to change user’s smb password. –a option specifies that the username following should be added to the local smbpasswd file.

If any valid users option is not specified, then all samba users can access the shared data. By Default shared permission is on writable=no means read only sharing. Write list option is used to allow write access on shared directory to certain users or group members.

To allow access the shared directory only from certain network or hosts, there is a option hosts allow= host or network. If this option is applied on global option, then it will apply to all shared directory.

Do the following steps as:

1. vi /etc/exports

/local *.example.com(rw,sync) trusted.cracker.org(ro,sync)

service nfs start | restart

service portmap start | restart

chkconfig nfs on

chkconfig portmap on

In Linux to share the data we use the /etc/exports file. Pattern is:

Path client(permission)

Shared Directory Path, Client can be single host or domain name or ip address. Permission should specify without space with client lists in parentheses. NFS is RPC service so portmapper service should restart after starting the nfs service. We can specify multiple clients’ list separating by space with different shared option.