Network infrastructure services: NTP, SNMP, PXE and IPAM
You set up the quiet heroes of every network — time sync, SNMP, network boot and address management — and see how devices rely on them.
Level 201 · 17 lessons · 15 practice labs
Lessons
Time
- Why time matters: logs, certificates, Kerberos
- Client time sync with chrony
- Serving NTP to the local network
- NTS and NTP security
- Short task: fix a server whose clock is drifting
SNMP
- SNMP: manager, agent, MIB, OID
- Reading devices with snmpwalk and snmpget
- snmpd configuration and community strings
- Authentication and encryption with SNMPv3
- Receiving events with SNMP traps
- Short task: collect the interface counters of every device
Boot and address management
- Setting up a TFTP server
- Booting from the network with PXE
- DHCP relay: serving addresses to another subnet
- IP address management: inventory and avoiding clashes (NetBox)
- Short task: boot a test machine from the network
Wrap-up
- Capstone: time, monitoring and boot services for a new office
Practice labs
- Clock minutes behind: chrony is asking the wrong server: Point the chrony configuration on the Kuzey Logistics server at the lab NTP server and show the synchronised state in chronyc tracking.
- Time will not sync although the server is up: Find why the client gets no NTP replies (firewall, wrong source address or closed port), fix it and prove a reachable source with chronyc sources.
- Logins rejected because of clock skew: Measure the clock offset between two Atlas Clinic servers, find the cause of the drift (broken drift file, missing makestep, single source) and bring the offset under one second, documented with logs.
- Serve time to the office: make chrony a server: Configure chrony to serve only the given office subnet and show a client synchronising from it.
- Lock down an NTP server open to everyone: Restrict the NTP server that answers every network so it serves only internal subnets with management queries disabled, and prove an outside test host is refused.
- Authenticated time: moving to NTS: Build an NTS-enabled time server for Silverwater Municipality, solve the certificate and port problems and show the client authenticated over NTS in chronyc authdata.
- A first look at a device over SNMP: Pull the uptime, system name and interface list from the lab router with snmpget and snmpwalk and save them to a text file.
- snmpwalk keeps timing out: Find why the management server cannot read the device (wrong community, access list, listening address), fix snmpd and pull the interface counters successfully.
- Collect every device’s error counters into one report: Write a script that walks the given device list over SNMP, tabulates input/output errors and discards per interface and flags the interface that is failing.
- From v2c to v3: the first SNMPv3 user: Create an SNMPv3 user with authentication and privacy in snmpd, disable v2c access and show that reads work only over v3.
- Get a trap when a link goes down: Set up a trap receiver with snmptrapd, configure the device to send traps on interface state changes, then shut an interface and prove the trap is logged.
- Clear-text SNMP audit: Capture SNMP traffic on the Pinecrest Bank lab network, list the devices leaking clear-text community strings, move all of them to SNMPv3 and show a fresh capture with no clear text left.
- The PXE client cannot find its boot file: Fix the missing or misnamed boot file on the TFTP server and the filename option in DHCP, and show the test machine booting from the network.
- Machines on the new floor get no address: Set up a DHCP relay on the router for clients on the separate subnet, add that subnet’s scope on the server and show with tcpdump that the client gets an address from the right range.
- The spreadsheet addresses do not match reality: Compare Orchid Hotel’s address spreadsheet with a live scan of the network, find clashing, unregistered and apparently free addresses and import the corrected inventory into IPAM.
About this course
You set up the quiet heroes of every network — time sync, SNMP, network boot and address management — and see how devices rely on them.
What you will learn
- Time
- SNMP
- Boot and address management
- Wrap-up
Prerequisites
Finishing the level 101 courses of the same path, or knowing those topics, is enough.
Lab environment
Lessons run in your own Kali Linux terminal in the browser, connected to a private lab network. Nothing to install.
Frequently asked questions
- Is this course right for my level?
- The course is at level 201; it assumes you know the topics of the lower-level courses.
- Is there anything to install?
- No. Every lesson runs in your own lab environment that opens in the browser.
- How do lessons work?
- Each lesson has 8 to 10 steps and a short quiz. Early steps show the command to type, later steps give less help; if two attempts fail, the solution opens.
- Can I try it for free?
- Yes. The first three lessons of every course are free.