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Q1. What are the new flags which RSTP BPDU's introduces? Q2. A user is unable to SSH the server, how do you troubleshoot this? Q3. What happens when you type google.com on your web browser? Q4. Why ARP is used? Different types of ARP Q5. DNS query is resolved then TCP handshake and at last HTTP packets exchanged. Q6. Explain DORA process Q7. How to motivate a customer if case is on Escalation edge ? Q8. ++Spanning tree and Troubleshooting of switching network Q9. ++In depth understanding of basic networking and troubleshooting
avatar

Network Engineer

Interviewed at Movate

3.6★
Sep 26, 2023

Q1. What are the new flags which RSTP BPDU's introduces? Q2. A user is unable to SSH the server, how do you troubleshoot this? Q3. What happens when you type google.com on your web browser? Q4. Why ARP is used? Different types of ARP Q5. DNS query is resolved then TCP handshake and at last HTTP packets exchanged. Q6. Explain DORA process Q7. How to motivate a customer if case is on Escalation edge ? Q8. ++Spanning tree and Troubleshooting of switching network Q9. ++In depth understanding of basic networking and troubleshooting

1. OSI Ref Model/TCP-IP Model · Explanation of each layer · Protocols at each layer 2. ARP · Packet structure ARP, GARP · Diff between ARP & GARP 3. Ethernet Frame · Fields in Ethernet II frame · Size of Ethernet Frame · LLC & MAC Sublayer 4. IP · Fields in IP header · Importance of Identification field, Flags, Fragment Offset · Fragmentation-Importance, Detailed understanding of how packet is reassembled · Path MTU Discovery 5. TCP · 3 way handshake · Parameters Informed, negotiated in TCP · Fields in TCP header · Windowing in TCP · Purpose of Sequence, Ack number · Window Size , MSS, Windows Scale Factor, SACK · Zero Window · Diff between MSS & MTU · Flags -SYN,ACK,FIN,RST,PSH,URG · Diff between Push & Urg , Purpose of RST bit · Segmentation · 4 way close · Flow Control –Sliding Window · Error Control – TCP retransmissions 6. FTP · How Active & Passive FTP works · PORT & PASV command · Troubleshooting FTP issues 7. Traceroute , ICMP, Ping · How Traceroute, Tracert works · ICMP message in traceroute · ICMP Type & Code (Type 8, Type 0, Type 3, Type 11) · Meaning of traceroute output 8. Switching & Routing Basics · Working of a Layer 2 switch · MAC Table, CAM Table , ARP Table · Static & Default Route 9. Firewall · Stateful vs stateless Firewall · Parameters in a Session Table · NAT , PAT · TCP Packet through Firewall , SYN check, Sequence check · FTP connection through Firewall, Troubleshooting · Deep Packet Inspection / ALG · Transparent Firewall · High Availability – Active/Standby , Active/Active , How Standby knows if Active is down · SYN Flood Attack & Mitigation · IP spoofing & Mitigation 10. VPN · Need for VPN · Types of VPN · Phase 1 & Phase 2 messages – Main mode, Aggressive Mode, Quick Mode · Need for 2 Phases in IPsec · Symmetric & Asymmetric keys, Hash & HMAC,DH group · Troubleshooting if various messages not received in IPsec (Msg1,Msg2,Msg3,Msg4,Msg5,Msg6) · Why Phase 1 is needed · Reasons why VPN Phase 1 does not come up · VPN Phase 1 up , Phase 2 down – Troubleshoot · VPN Phase 1 up , Phase 2 up , Traffic not flowing – Troubleshoot · Traffic Flowing but Latency Issue-Troubleshoot · Tunnel Mode & Transport Mode · Overlapping subnets · NAT-T(NAT Discovery) –VPN msgs for NAT-T Negotiation & Discovery · ESP,AH · Replay Attack & Mitigation · Ports to be allowed on Firewall for VPN
avatar

Network Engineer

Interviewed at Movate

3.6★
Aug 24, 2016

1. OSI Ref Model/TCP-IP Model · Explanation of each layer · Protocols at each layer 2. ARP · Packet structure ARP, GARP · Diff between ARP & GARP 3. Ethernet Frame · Fields in Ethernet II frame · Size of Ethernet Frame · LLC & MAC Sublayer 4. IP · Fields in IP header · Importance of Identification field, Flags, Fragment Offset · Fragmentation-Importance, Detailed understanding of how packet is reassembled · Path MTU Discovery 5. TCP · 3 way handshake · Parameters Informed, negotiated in TCP · Fields in TCP header · Windowing in TCP · Purpose of Sequence, Ack number · Window Size , MSS, Windows Scale Factor, SACK · Zero Window · Diff between MSS & MTU · Flags -SYN,ACK,FIN,RST,PSH,URG · Diff between Push & Urg , Purpose of RST bit · Segmentation · 4 way close · Flow Control –Sliding Window · Error Control – TCP retransmissions 6. FTP · How Active & Passive FTP works · PORT & PASV command · Troubleshooting FTP issues 7. Traceroute , ICMP, Ping · How Traceroute, Tracert works · ICMP message in traceroute · ICMP Type & Code (Type 8, Type 0, Type 3, Type 11) · Meaning of traceroute output 8. Switching & Routing Basics · Working of a Layer 2 switch · MAC Table, CAM Table , ARP Table · Static & Default Route 9. Firewall · Stateful vs stateless Firewall · Parameters in a Session Table · NAT , PAT · TCP Packet through Firewall , SYN check, Sequence check · FTP connection through Firewall, Troubleshooting · Deep Packet Inspection / ALG · Transparent Firewall · High Availability – Active/Standby , Active/Active , How Standby knows if Active is down · SYN Flood Attack & Mitigation · IP spoofing & Mitigation 10. VPN · Need for VPN · Types of VPN · Phase 1 & Phase 2 messages – Main mode, Aggressive Mode, Quick Mode · Need for 2 Phases in IPsec · Symmetric & Asymmetric keys, Hash & HMAC,DH group · Troubleshooting if various messages not received in IPsec (Msg1,Msg2,Msg3,Msg4,Msg5,Msg6) · Why Phase 1 is needed · Reasons why VPN Phase 1 does not come up · VPN Phase 1 up , Phase 2 down – Troubleshoot · VPN Phase 1 up , Phase 2 up , Traffic not flowing – Troubleshoot · Traffic Flowing but Latency Issue-Troubleshoot · Tunnel Mode & Transport Mode · Overlapping subnets · NAT-T(NAT Discovery) –VPN msgs for NAT-T Negotiation & Discovery · ESP,AH · Replay Attack & Mitigation · Ports to be allowed on Firewall for VPN

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