Red Hat Certified Engineer Tutorials
Installation and Configuration / Configure User/Host-based Security
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Subtitles of the Movie (Red Hat Certified Engineer / Installation and Configuration / Configure User/Host-based Security)
There are three basic ways to configure user- and or host-based security for a network service. You could do it, in most cases, in the service-specific configuration file. For TCP-based services you could use TCP Wrappers, and you could also configure a firewall based on iptables commands. We've discussed each of these in detail in other videos, so this should just be a review. First, most services support some level of at least host-based security using IP addresses, host names and or domain names. For example in NFS the following line limits access to the home directory, to systems in the example dot net domain. Sometimes you may want to substitute IP addresses, say when DNS service is not available, or not reliable. User-based security can't be configured in all service-specific configuration files, but it is possible in many. For example, in a Samba configuration file, the following directive: valid users equals mary fred limits access to those users with the Mary and Fred usernames. Of course this assumes there is some Windows-type authentication database that includes these users. Next, user- and host-name based security can be configured using TCP Wrappers, but that works only for services that use TCP packets; while that's most services, that doesn't apply to every Linux service. That can be checked in the etc slash services configuration file. TCP Wrappers are configured in the c slash hosts dot allow and etc slash hosts dot deny, read in that order. In other words, if a host, a user, or service is allowed in etc slash hosts dot allow, it doesn't matter what's in etc slash hosts dot deny. Finally, host access can be regulated through a firewall, generally by port number. It's configurable with the iptables command. For the current firewall for IPv4 addresses, run the iptables dash L, that's a capital L command. You could also use ip6tables dash L to see the parallel firewall for IPv6 networking. The easiest way to configure a firewall is with the Security Level Configuration tool. But that's not always enough, so you need to know how to insert iptables commands. We've shown you in detail in another video. When you do, just make sure to save the changes with the iptables-save command and ip6tables-save commands. Those are the basic principles of configuring user- and host-based security for a service.
Tutorial Information
| Course: | Red Hat Certified Engineer |
| Author: | Michael Jang |
| SKU: | 33845 |
| ISBN: | 1-934743-47-X |
| Release Date: | 2008-01-18 |
| Duration: | 6.5 hrs / 94 lessons |
| Captions: | No |
| Compatibility: |
Vista/XP/2000, OS X, Linux QuickTime 7, Flash 8 |
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