Curated interview practice questions with answers. These are practice scenarios, not a verified list of past interview questions.
About HCLTech hiring for CCNA roles
HCLTech is an Indian multinational IT services and consulting company providing digital engineering, cloud, infrastructure, software products and data services. It works with clients in sectors such as financial services, manufacturing, life sciences and telecom. In India it hires for software engineers, test engineers, data analysts and data engineers through campus drives and programmes like TechBee.
For CCNA roles, this HCLTech practice set focuses most on STP and EtherChannel (7), Network Security (6), Wireless and Automation (5), IP Addressing and Subnetting (4). It has 16 easy, 14 medium questions, so you can start easy and work up to the harder ones.
Company type
IT services
Headquarters
Noida, India
Main India offices
Noida, Chennai, Bengaluru, Hyderabad, Lucknow
HCLTech CCNA interview process
Online assessment (aptitude + technical)
Technical interview
Managerial round
HR round
Typical pattern based on public candidate experiences. Rounds vary by role, team and year.
Solved for HCLTechStart practicing
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Redundant Layer 2 links create loops, and Ethernet frames have no TTL, so broadcasts circulate forever, causing broadcast storms, MAC table instability and duplicate frames. STP (802.1D) blocks redundant paths so there is one loop-free path to every switch, and unblocks a backup link if the active one fails. Without it, a single loop can take down a whole campus within seconds.
Set priorities on the intended primary and secondary roots, then verify.
spanning-tree mode rapid-pvst
spanning-tree vlan 10,20 root primary
! on the backup switch
spanning-tree vlan 10,20 root secondary
show spanning-tree vlan 10
show spanning-tree root
show spanning-tree summary
Put members in a channel group with mode active, then configure the port-channel.
interface range GigabitEthernet1/0/47 - 48
channel-group 1 mode active
interface Port-channel1
switchport mode trunk
switchport trunk allowed vlan 10,20,99
port-channel load-balance src-dst-ip
show etherchannel summary
A switch reads the source MAC of each incoming frame and records it with the port in the MAC address table. For forwarding it looks up the destination MAC: a known unicast goes out one port, while unknown unicast, broadcast and most multicast frames are flooded in the VLAN. Entries age out after 300 seconds by default. Check with show mac address-table.
05
What are the STP port states and timers in classic 802.1D?
States are blocking, listening, learning, forwarding and disabled. Timers are hello 2 seconds, forward delay 15 seconds and max age 20 seconds. A port moves from blocking through listening and learning, each 15 seconds, so convergence can take 30 to 50 seconds. That delay is why Rapid STP and PortFast are used in modern networks.
06
What is the difference between standard and extended ACLs?
Standard ACLs (1 to 99 and 1300 to 1999) match only the source IP, so they should be placed close to the destination. Extended ACLs (100 to 199 and 2000 to 2699) match protocol, source, destination and ports, so they can be placed close to the source to drop unwanted traffic early. Named ACLs work for both and allow editing individual lines by sequence number.
07
How do you configure inter-VLAN routing on a Layer 3 switch with SVIs?
Enable routing and create an SVI per VLAN as the gateway.
ip routing
interface vlan 10
ip address 192.168.10.1 255.255.255.0
ip helper-address 10.0.0.50
no shutdown
interface vlan 20
ip address 192.168.20.1 255.255.255.0
no shutdown
show ip route connected
Variable Length Subnet Masking means using different prefix lengths inside one address block, so each subnet is sized to its need. You allocate the largest subnets first, then smaller ones, to avoid overlaps. For example, from 10.1.1.0/24 you could give a 100-user LAN a /25, a 50-user LAN a /26, and point-to-point WAN links /30 or /31. It saves address space compared with fixed-length subnetting.
The TCP/IP model has four or five layers. Its Application layer covers OSI layers 5 to 7, Transport maps to Layer 4, Internet maps to Layer 3, and Network Access (or Link plus Physical) covers layers 1 and 2. CCNA uses the five-layer version. Real protocols such as HTTP, TCP and IP are defined by the TCP/IP suite, so it is the practical model.
10
What is NTP and why does time matter on network devices?
NTP synchronises clocks over UDP 123 using a hierarchy of strata, where stratum 1 servers connect to an atomic or GPS clock. Correct time matters because syslog and incident timelines must line up across devices, certificates and authentication protocols check time, and logs are legal evidence. Devices can be NTP clients, servers or peers, and NTP authentication protects against fake time sources.
11
Explain root port, designated port and blocked port.
Every non-root switch picks one root port, its best path to the root based on lowest root path cost, then lowest sender bridge ID, then lowest sender port ID. On each segment, the switch with the best path becomes the designated port and forwards. Every remaining port becomes non-designated and blocks. All ports on the root bridge are designated.
Syslog has eight levels from 0 to 7: emergency, alert, critical, error, warning, notification, informational and debugging. A useful memory line is Every Awesome Computer Engineer Will Need Ice cream Daily. Setting logging trap 6 sends levels 0 to 6 to the server. Syslog uses UDP 514 by default, and logs should carry timestamps with service timestamps log datetime msec.
13
What is AAA and the difference between TACACS+ and RADIUS?
AAA stands for Authentication (who you are), Authorization (what you can do) and Accounting (what you did). TACACS+ uses TCP 49, encrypts the whole payload and separates authentication from authorization, so it is preferred for device administration with per-command control. RADIUS uses UDP 1812 and 1813, encrypts only the password and is used for network access such as 802.1X and VPN.
802.11n (Wi-Fi 4) works on 2.4 and 5 GHz with MIMO. 802.11ac (Wi-Fi 5) is 5 GHz only with wider channels and MU-MIMO downlink. 802.11ax (Wi-Fi 6 and 6E) adds OFDMA, BSS colouring and target wake time, and 6E adds the 6 GHz band. 802.11be (Wi-Fi 7) adds 320 MHz channels and multi-link operation. India opened part of the 6 GHz band for indoor use.
Switches exchange BPDUs and the one with the lowest bridge ID becomes root. The bridge ID is the priority (default 32768 plus the VLAN number in PVST) followed by the MAC address, so if priorities tie, the lowest MAC wins. Because the oldest switch often has the lowest MAC, you should set priority manually, for example spanning-tree vlan 10 root primary on the core.
A client asks its configured resolver, for example for www.example.com. If it is not cached, the resolver queries a root server, which refers it to the .com TLD server, which refers it to the authoritative server for example.com, which returns the A or AAAA record. The answer is cached for its TTL. DNS uses UDP 53 for most queries and TCP 53 for zone transfers and large replies.
DHCP snooping classifies ports as trusted (uplinks toward real DHCP servers) or untrusted (user ports). Server messages such as Offer and Ack arriving on untrusted ports are dropped, which stops rogue DHCP servers. It also builds a binding table of MAC, IP, VLAN and port, which Dynamic ARP Inspection and IP Source Guard use. Rate limits on untrusted ports prevent DHCP starvation.
18
Two hosts are in the same VLAN but one has mask /24 and the other /25. What problems may occur?
Each host decides local or remote using its own mask. With 192.168.1.10/24 and 192.168.1.200/25, the first thinks .200 is local and ARPs directly, but the second sees .10 as remote and sends replies to its gateway. Traffic can become one-way or asymmetric and may break completely if the gateway does not route it back. Fix the mask so both match the design.
19
How do you stay updated on network security threats?
Situation: as a fresher I realised many interview questions asked about recent attacks. Task: build a habit of learning. Action: I follow vendor security advisories, CERT-In alerts and a few security newsletters, practise in a home lab with packet captures, and read the release notes of devices we use. Result: I can explain current threats in interviews and suggested patching a vulnerable IOS version in my internship.
WPA2 uses AES-CCMP; WPA2-Personal uses a pre-shared key that is vulnerable to offline dictionary attacks, and WPA2-Enterprise uses 802.1X with RADIUS. WPA3-Personal replaces PSK with SAE, which resists offline guessing and gives forward secrecy. WPA3-Enterprise offers a 192-bit mode. WPA3 requires protected management frames. Open networks can use OWE for encryption without passwords.
EtherChannel bundles 2 to 8 physical links into one logical port-channel. STP sees it as one link, so all members forward instead of one being blocked. It adds bandwidth and redundancy, as one member failing does not drop the channel. Traffic is load-balanced per flow using a hash of MAC, IP or port fields, so a single flow still uses only one member link.
22
What is the difference between site-to-site and remote-access VPNs?
A site-to-site VPN connects whole networks, usually two routers or firewalls, using an always-on IPsec tunnel, so users do not need any client. A remote-access VPN connects individual users from laptops or phones to the company network using a client with TLS or IPsec, and authenticates each user. Both encrypt traffic over the internet to provide confidentiality and integrity.
Control and Provisioning of Wireless Access Points is the protocol between lightweight APs and the WLC. It builds two tunnels: a control tunnel on UDP 5246, encrypted with DTLS, and a data tunnel on UDP 5247 that carries client traffic in central switching mode. In FlexConnect or local switching mode, client data is switched locally at the AP instead of being tunnelled.
24
What is the structure of an IPv6 address and how is it shortened?
IPv6 addresses are 128 bits written as eight groups of four hex digits separated by colons. Leading zeros in each group can be dropped, and one run of consecutive all-zero groups can be replaced with :: only once. For example 2001:0db8:0000:0000:0000:0000:0000:0001 becomes 2001:db8::1. A typical LAN uses a /64 prefix.
25
What are the data plane, control plane and management plane?
The data plane forwards packets, using tables such as the FIB and MAC table, ideally in hardware. The control plane builds those tables using protocols like OSPF, STP and ARP. The management plane is how admins and tools interact with the device, through SSH, SNMP, syslog and APIs. Separating them helps understanding of SDN, where the control plane can be centralised.
26
Users can connect to the corporate SSID but get no IP address. What do you check?
Association works, so the issue is between the AP or WLC and DHCP. I check the WLAN is mapped to the right dynamic interface and VLAN, that the VLAN is allowed on the WLC and AP trunks, and that DHCP relay or helper is set on the VLAN gateway. In FlexConnect local switching, I check the AP switchport trunk and VLAN mapping. Finally I check the DHCP scope.
27
How do you approach working in a 24x7 network operations shift?
Situation: I joined a NOC that ran rotating shifts. Task: stay effective and keep handovers clean. Action: I followed runbooks, kept a shift log of every alert and action, raised early escalations for anything outside my scope and used quiet hours to lab new topics. Result: I handled shift incidents within SLA, earned positive feedback for clear handovers and was moved to the L2 team in a year.
28
How does a router choose the best route to a destination?
First it uses longest prefix match: the most specific matching prefix wins, so 10.1.1.0/24 beats 10.1.0.0/16. If the same prefix comes from different sources, the lowest administrative distance wins. If the same protocol offers several paths, the lowest metric wins, and equal metrics can be load-balanced with ECMP. Only the winners are installed in the routing table.
29
Explain password security best practices for network devices.
Use enable secret, not enable password, so the hash is strong (type 8 or 9 on modern IOS). Create local users with secret, enforce minimum length with security passwords min-length, and use AAA with TACACS+ for central control. Disable Telnet, use SSH v2, set exec-timeout on lines, and add login block-for to slow brute force. Avoid type 7 passwords, which are easily reversed.
30
How do you verify IP settings and test from a Windows and Linux host?
Windows and Linux both have a small core toolkit.
ipconfig /all (IP, mask, gateway, DNS, DHCP server)
ipconfig /release && ipconfig /renew
arp -a
ip addr ; ip route ; ip neigh
resolvectl status
nslookup example.com
Add ping and tracert or traceroute to test the path.
Tips to crack the HCLTech CCNA interview
Revise programming basics, SQL and networking fundamentals, as HCLTech roles span applications and infrastructure services.
Learn about HCLTech's software products business, HCLSoftware, and its engineering and R&D services.
Be clear and honest about your preferred domain and shift flexibility, as some roles involve support or global time zones.
Keep a one-minute story ready for every project on your CV: problem, your part, tools, result.
Practise the hard questions on this page aloud; HCLTech interviewers usually ask follow-ups on your first answer.
Frequently asked questions
How many rounds are there in the HCLTech CCNA interview?
Candidates usually go through 4 stages: Online assessment (aptitude + technical); Technical interview; Managerial round; HR round. The exact rounds change with the role, team, location and your experience, so confirm the process with the recruiter.
Which topics should I prepare for the HCLTech CCNA interview?
This practice set leans on STP and EtherChannel (7), Network Security (6), Wireless and Automation (5), IP Addressing and Subnetting (4). Revise those first, then practise explaining one or two of your own projects end to end, because most HCLTech interviewers ask you to walk through real work.
Are these the exact questions asked at HCLTech?
No. These are curated practice questions that match the skills and difficulty usually tested in it services interviews like HCLTech's. They are not a leaked or verified list of past questions.
Where does HCLTech hire CCNA professionals in India?
HCLTech has large teams in Noida, Chennai, Bengaluru, Hyderabad, Lucknow. Openings and locations change often, so check the HCLTech careers page and filter by city and experience.