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TCP Wrapper
2016/02/21 |
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This is the example for TCP Access Control by TCP Wrapper.
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| [1] | Install TCP Wrapper. |
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[root@dlp ~]# yum -y install tcp_wrappers
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| [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. |
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[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'
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| [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. |
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[root@dlp ~]#
vi /etc/hosts.deny sshd: ALL
[root@dlp ~]#
vi /etc/hosts.allow sshd: 10.0.0.
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| [4] | For the case to allow the accesses to vsftpd from 'host.example.domain'. |
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[root@dlp ~]#
vi /etc/hosts.deny vsftpd: ALL
[root@dlp ~]#
vi /etc/hosts.allow vsftpd: host.example.domain
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| [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'. |
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[root@dlp ~]#
vi /etc/hosts.deny ALL: ALL
[root@dlp ~]#
vi /etc/hosts.allow ALL: .example.domain 10.0.1.
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