Understanding labeled networking
Another approach to further fine-tune access controls on the network level is to introduce labeled networking. With labeled networking, security information passes on between hosts (unlike SECMARK, which only starts when the netfilter subsystem receives the packet, and whose marking never leaves the host). This is also known as peer labeling, as the security information passes on between hosts (peers).
The advantage of labeled networking is that security information remains across the network, allowing end-to-end enforcement on mandatory access-control settings between systems as well as retaining the sensitivity level of communication flows between systems. The major downside, however, is that this requires an additional network technology (protocol) that can manage labels on network packets or flows.
SELinux currently supports two implementations as part of the labeled networking approach: NetLabel and labeled IPsec. With NetLabel, two implementations...
