36 practice questions with answers for CCNA interviews in Kochi.
CCNA jobs in Kochi
Kochi's Infopark and SmartCity host IT-services firms, product companies and start-ups, making it Kerala's largest tech job market along with Thiruvananthapuram. Testing and data roles are common in its service and product teams.
Below are 36 questions that match the mix of service, product and domain employers hiring network support engineers in Kochi.
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01
What are the IPv4 address classes and private ranges?
Class A is 1 to 126 with a default /8, Class B is 128 to 191 with /16, Class C is 192 to 223 with /24, Class D 224 to 239 is multicast and Class E is reserved. RFC 1918 private ranges are 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. 127.0.0.0/8 is loopback and 169.254.0.0/16 is APIPA link-local. Today addressing is classless (CIDR).
02
How would you represent an interface configuration in JSON and YAML?
The same data in both formats.
JSON:
{
"interface": "GigabitEthernet0/1",
"enabled": true,
"ipv4": ["192.168.1.1/24"]
}
YAML:
interface: GigabitEthernet0/1
enabled: true
ipv4:
- 192.168.1.1/24
Use one trunk link and a subinterface per VLAN with 802.1Q encapsulation.
interface GigabitEthernet0/0
no shutdown
interface GigabitEthernet0/0.10
encapsulation dot1Q 10
ip address 192.168.10.1 255.255.255.0
interface GigabitEthernet0/0.20
encapsulation dot1Q 20
ip address 192.168.20.1 255.255.255.0
The switch port facing the router must be a trunk.
04
A PC in VLAN 20 cannot reach a PC in VLAN 30. What do you check?
First I check each PC has the correct IP, mask and gateway for its VLAN. Then I confirm the switch ports are in the right VLANs with show vlan brief, and that the trunk to the Layer 3 device allows both VLANs using show interfaces trunk. On the Layer 3 device I check the SVIs or subinterfaces are up and have the right IPs, and that no ACL blocks the traffic.
05
A server team says an ACL you applied blocked all traffic, including allowed services. What happened?
Most likely the ACL lacks a permit for normal traffic, so the implicit deny dropped everything, or the order put a broad deny above the specific permits. It may also be applied in the wrong direction or on the wrong interface. I check show access-lists for hit counts, fix the sequence by inserting lines, and add a final permit or the needed entries. I always test ACLs with a rollback timer.
06
Explain the NAT terms inside local, inside global, outside local and outside global.
Inside local is the private address of an inside host, for example 192.168.1.10. Inside global is the public address that represents it outside, for example 203.0.113.5. Outside global is the real address of the remote host. Outside local is how the remote host appears to inside users, usually the same as outside global unless destination NAT is used. show ip nat translations displays these columns.
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.
The SSID is the network name users see. The BSSID is the MAC address of the access point radio serving a BSS, the basic service set of one AP and its clients. An ESS is multiple BSSs sharing the same SSID connected by a wired distribution system, so clients can roam between APs. Each AP can broadcast several SSIDs, each with its own BSSID.
09
How do you use CDP and LLDP to discover neighbours?
CDP is a proprietary Layer 2 discovery protocol enabled by default on IOS; LLDP is the open IEEE 802.1AB standard.
show cdp neighbors
show cdp neighbors detail
configure terminal
lldp run
show lldp neighbors detail
Detail output shows the neighbour's IP, platform and port. Disable CDP on internet-facing ports with no cdp enable.
LACP (802.3ad, now 802.1AX) is the open standard with modes active and passive; at least one side must be active. PAgP is proprietary with modes desirable and auto; at least one side must be desirable. Mode on forces the channel with no negotiation, which can cause loops if the other side is not configured. LACP is preferred because it works with servers, firewalls and other vendors.
11
Tell me about a time you took initiative beyond your assigned work.
Situation: our team got many Wi-Fi complaints but had no data. Task: nobody had asked, but I wanted to find the cause. Action: I did a walk-through survey with a free tool, mapped channels and signal, and found three APs on the same 2.4 GHz channel and one dead AP. I shared a short report with fixes. Result: after the changes, Wi-Fi tickets dropped by about 60 percent in a month.
Member interfaces must have the same speed and duplex, the same mode (access or trunk), the same access VLAN or the same native and allowed VLAN list on trunks, and compatible negotiation modes. Mismatched settings put members into suspended state. Configure settings on the port-channel interface so they are pushed to members, and verify with show etherchannel summary.
Allow web traffic from one subnet to a server and block the rest of that subnet.
ip access-list extended WEB-ONLY
10 permit tcp 192.168.10.0 0.0.0.255 host 10.0.0.80 eq 443
20 deny ip 192.168.10.0 0.0.0.255 10.0.0.0 0.0.0.255
30 permit ip any any
interface vlan 10
ip access-group WEB-ONLY in
show access-lists WEB-ONLY
14
Auditors find that network devices use shared admin passwords and Telnet. What is your remediation plan?
Disable Telnet with transport input ssh, enable SSH v2, and move admin login to AAA with TACACS+ so each engineer has a personal account with command authorisation and accounting logs. Keep one local fallback account in a password vault. Restrict VTY access with an ACL to the management subnet. Roll out with automation, test on a pilot, then document it for the audit.
Mark interfaces, match inside hosts with an ACL and overload the outside interface.
interface GigabitEthernet0/1
ip nat inside
interface GigabitEthernet0/0
ip nat outside
access-list 1 permit 192.168.0.0 0.0.255.255
ip nat inside source list 1 interface GigabitEthernet0/0 overload
show ip nat translations
16
An EtherChannel shows members in suspended state. What do you check?
Suspended (s) usually means a configuration mismatch between members or with the far end. I compare speed, duplex, trunk mode, native VLAN and allowed VLANs on each member and the port-channel with show run interface, check LACP modes on both sides, and look at logs. I fix the config on the port-channel, then shut and no shut members so they rejoin. show etherchannel summary should show P flags.
17
How do you configure SSH access on a switch or router?
SSH needs a hostname, domain name, RSA keys, a local user and VTY lines restricted to SSH.
hostname R1
ip domain-name lab.local
crypto key generate rsa modulus 2048
ip ssh version 2
username admin privilege 15 secret Adm1nPass
line vty 0 4
login local
transport input ssh
Configure the same group and virtual IP on both switches, with higher priority on the active one.
interface vlan 10
ip address 192.168.10.2 255.255.255.0
standby version 2
standby 10 ip 192.168.10.1
standby 10 priority 110
standby 10 preempt
show standby brief
Hosts use 192.168.10.1 as their gateway.
19
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.
20
Find the network, broadcast and usable range for 172.16.45.200/21.
A /21 mask is 255.255.248.0, so the interesting octet is the third with block size 8. 45 falls in the block starting at 40 (40 to 47).
Network: 172.16.40.0
Broadcast: 172.16.47.255
Usable: 172.16.40.1 - 172.16.47.254
Hosts: 2^11 - 2 = 2046
VLAN Trunking Protocol shares VLAN definitions from a server switch to clients in the same VTP domain. Modes are server, client, transparent and off. The risk is that a switch with a higher configuration revision number can overwrite and wipe VLANs across the domain. Many networks use transparent mode or VTP version 3 with a primary server to avoid this.
22
What are the key elements of a security program for a network?
A security program combines user awareness training, physical access control, and technical controls such as strong authentication, firewalls, IPS, VPNs and patching. It is built around the CIA triad: confidentiality, integrity and availability. Policies define what is allowed, and logging and monitoring detect problems. CCNA focuses on device hardening, ACLs, Layer 2 security, AAA, VPNs and wireless security.
23
What are the default STP path costs for common link speeds?
With short (802.1D revised) costs: 10 Mbps is 100, 100 Mbps is 19, 1 Gbps is 4 and 10 Gbps is 2. With the long pathcost method, 1 Gbps is 20000 and 10 Gbps is 2000, which distinguishes higher speeds. Root path cost is the sum of costs on ports toward the root, and the lowest total wins when choosing root ports.
24
Which commands would you use to test end-to-end reachability and find where packets stop?
ping tests reachability and round-trip time, and traceroute shows each Layer 3 hop.
R1# ping 10.2.2.2 source Loopback0
R1# traceroute 10.2.2.2
PC> tracert 10.2.2.2
An extended ping lets you set source, size and the DF bit to test MTU. Where traceroute shows asterisks, that hop is dropping or filtering ICMP.
25
Your company is running out of IP addresses on a /24 user subnet. What options do you have?
Options: expand to a /23 if the adjacent block is free and update the router and DHCP scope; create a new VLAN and subnet for some users, which also limits broadcast size; shorten DHCP lease times if many guest devices hold leases; and move printers, phones and IoT devices to their own subnets. Long term, plan an addressing scheme with growth headroom and consider dual-stack IPv6.
26
Which QoS classes would you build for a typical branch WAN?
A simple five-class model works for most branches.
Voice (EF) priority queue, about 10 percent
Video (AF41) guaranteed 20-25 percent
Signalling (CS3) 5 percent
Business apps (AF21) 25-30 percent
Default (BE) remaining, with fair queuing
Scavenger (CS1) small share for backups and updates
27
Tell me about a time you solved a difficult network outage.
Situation: a branch lost access to the data center during month-end close. Task: restore service fast. Action: I worked bottom-up, found the WAN link up but OSPF stuck in EXSTART, and traced it to an MTU change by the provider. I set ip ospf mtu-ignore as a temporary fix and raised a ticket for the MTU. Result: service was back in 25 minutes and I documented the check in our runbook.
28
Write a simple Ansible playbook that configures NTP on IOS devices.
Ansible is agentless, uses SSH or APIs, writes playbooks in YAML and uses a push model, so it is the most popular for network devices. Puppet uses an agent, a declarative manifest language and a pull model. Chef uses Ruby-based recipes with an agent and pull model. Puppet and Chef are more common for servers. All support idempotent configuration management.
The client sends a SYN with an initial sequence number. The server replies with SYN-ACK, acknowledging the client sequence and sending its own. The client sends an ACK and the session is established. Closing uses FIN and ACK from each side. A firewall that sees repeated SYNs without the final ACK may be looking at a SYN flood attack.
31
What is a Layer 3 switch and how is it different from a router?
A Layer 3 switch forwards packets between VLANs in hardware using SVIs or routed ports, giving very high throughput with many Ethernet ports. A router usually has fewer ports but richer WAN features such as NAT, VPN, deep QoS, varied WAN interfaces and large routing tables. In campuses, Layer 3 switches handle inter-VLAN routing while routers or firewalls handle the edge.
32
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.
33
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.
34
A broadcast storm brought the network down after someone connected a cable between two wall ports. How do you prevent this?
Two wall ports patched to the same switch formed a loop. To stop it now, I find the port with rising broadcast counters and shut it. To prevent repeats, enable PortFast with BPDU Guard on all access ports, keep Rapid PVST+ running everywhere, add storm-control broadcast thresholds on access ports and enable errdisable recovery with a sensible interval.
Quality of Service gives different treatment to traffic types when links are congested. Voice needs low delay (under 150 ms one way), low jitter (under 30 ms) and low loss (under 1 percent), while bulk file transfer can wait. QoS tools classify and mark traffic, queue it with priority queues for voice, and police or shape rates. Without congestion QoS has no effect.
36
How do you back up and restore a device configuration?
Copy the config to a server and back.
copy running-config tftp://10.0.0.40/R1-backup.cfg
copy running-config scp://admin@10.0.0.40/R1.cfg
copy tftp://10.0.0.40/R1-backup.cfg running-config
configure replace flash:R1-good.cfg
archive
path flash:R1-archive
write-memory
configure replace gives a clean rollback instead of merging.
Few big employers listed in Kochi?
Many Kochi candidates also apply to teams in Bangalore and to remote or hybrid roles. Practise the Bangalore set as well.
Companies with large offices in Kochi include many IT services and product firms. Use their company pages below to practise employer-specific sets.
Are CCNA interviews in Kochi different from other cities?
The questions depend more on the company than the city. Kochi's mix of employers decides the style: Testing and data roles are common in its service and product teams
How do I find CCNA jobs in Kochi?
Shortlist companies with Kochi offices, keep your CV focused on CCNA projects, apply on company career pages and job portals with the Kochi filter, and practise the questions on this page before each interview.