1Z0-105 · Question #30
Which statement is true about the net_cls cgroup subsystem?
The correct answer is D. It tags network packets with an identifier. https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html- single/Resource_Management_Guide/
Question
Options
- AIt controls the throughput limits for network packets.
- BIt dynamically sets the priority of network traffic per network interface.
- CIt enforces a limit on the number of opened sockets.
- DIt tags network packets with an identifier.
How the community answered
(20 responses)- B10% (2)
- C15% (3)
- D75% (15)
Explanation
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html- single/Resource_Management_Guide/
Topics
Community Discussion
6
Carlos M.Mar 3, 2026D is correct. net_cls tags outgoing network packets with a classid identifier so tools like tc (traffic control) can classify and apply QoS policies to them, but it does not throttle throughput, set priorities directly, or limit sockets on its own.
Nina C.Mar 5, 2026Good clarification, and worth adding that net_prio is the sibling subsystem that actually does set per-interface network priority directly, which is probably why the exam writers included a distractor around that concept.
Nina C.Mar 12, 2026Spent 30 seconds on this one, "tags packets with an identifier" just felt right, D it is.
Wesley A.Mar 28, 2026I honestly went with B first because I was thinking about how traffic shaping works and assumed "classifying" meant setting priority per interface, but net_cls does not enforce or control anything on its own, it only tags packets with a class ID so that external tools like tc can act on them later. That distinction between tagging and enforcing is exactly the trap on this one.
Carlos M.Mar 29, 2026net_cls just stamps the packet and walks away, tc is the one that actually decides what happens to it, which is why you can have net_cls configured perfectly and still see zero traffic shaping if tc rules are not in place.
Fatima Z.Mar 21, 2026So net_cls just TAGS packets, not controls them, right? Why do people keep mixing it up with net_prio?