TCP Wrapper

TCP Wrapper 2016/02/21

	This is the example for TCP Access Control by TCP Wrapper.
[1]	Install TCP Wrapper.

[root@dlp ~]#  yum -y install tcp_wrappers

[2]	Make sure if a service can be under the TCP Wrapper control or not with the following command. If it includes a link to 'libwrap', it's possible.

[root@dlp ~]#  ldd /usr/sbin/sshd | grep wrap      libwrap.so.0 => /lib64/libwrap.so.0 (0x00007f01b4e2a000) # this service can be under TCP Wrapper control because it includes 'libwrap'

[3]	Access control by TCP Wrapper is configured in '/etc/hosts.allow' and '/etc/hosts.deny'.  The example below shows to set configuration which allows to access to sshd from 10.0.0.0/24.

[root@dlp ~]#  vi /etc/hosts.deny sshd: ALL [root@dlp ~]#  vi /etc/hosts.allow sshd: 10.0.0.

[4]	For the case to allow the accesses to vsftpd from 'host.example.domain'.

[root@dlp ~]#  vi /etc/hosts.deny vsftpd: ALL [root@dlp ~]#  vi /etc/hosts.allow vsftpd: host.example.domain

[5]	For the case to allow accesses to all services that can be under TCP Wrapper control only from 'example.domain' and '10.0.1.0/24'.

[root@dlp ~]#  vi /etc/hosts.deny ALL: ALL [root@dlp ~]#  vi /etc/hosts.allow ALL: .example.domain 10.0.1.