Chapter 1 of 6 · MikroTik MTCTCE
Packet Flow Diagram
Why the diagram matters, how packets travel through RouterOS, and how routing and bridging fit in.
- 2topics
- 10 minfast track
- 1diagrams and exhibits
Topics in this chapter
Take them in order, or jump to the one you need.
- 1Why the Packet Flow Diagram MattersLearn why the RouterOS packet flow diagram matters, which stages a packet passes through, and how simple examples trace across…Diagram5 min
- 2Routing, Bridging and Complex FlowsTrace routed, bridged and router local traffic through the RouterOS packet flow diagram, then work through port forwarding and…5 min
About this chapter
What this chapter covers
This chapter teaches you to read the RouterOS packet flow diagram, which is the map for every other topic in the exam.
The diagram shows the order in which RouterOS handles a packet, from the moment it enters an interface until it leaves. Firewall filter, NAT, mangle, connection tracking and queues all sit at fixed places on that map.
The chapter has one syllabus topic, and it is split over two pages so each stays readable.
How the topics fit together
The first page gives the big picture, and the second page applies it to routing, bridging and harder cases.
Every later chapter hangs off this line:
- Firewall: filter rules sit in the input, forward and output chains, NAT in dstnat and srcnat, and mangle in all five chains.
- Queues: shaping happens near the end of the path, so marks made earlier can be used there.
- Services: DNS, DHCP and the web proxy are local processes, so their traffic uses the input and output chains.
When a rule does not behave as you expect, ask first where on the diagram the packet is at that moment.
How to use these pages
Each topic page has the same shape, so you can skim for what you need.
- What it is: the idea in plain words.
- How it works: the mechanism, with diagrams and example commands.
- What to remember for the exam: the facts to memorise.
- Common mistakes: the classic traps.
- Check yourself: three questions to test your understanding.
Draw the diagram from memory after reading each page. Then trace a few packets across it with a pencil, for example a web request from a LAN host, a ping to the router and a reply from the router. The habit of tracing is worth more than memorising the picture.
Where RouterOS version 6 and version 7 differ, the pages say so. If a detail is not stated for a version, treat it as common to both.
Ready for more practice?
The full MikroTik MTCTCE question bank has 479 questions, with timed practice exams and an explanation for every answer.
This study guide is independent and is not affiliated with, endorsed by, or sponsored by MikroTik. Vendor names, certification names and exam codes are trademarks of their respective owners and are used for identification only.