- What is localhost and why would
ping localhostfail? - What is the similarity between “ping” & “traceroute” ? How is traceroute able to find the hops.
- What is the command used to show all open ports and/or socket connections on a machine?
- Is 300.168.0.123 a valid IPv4 address?
- Which IP ranges/subnets are “private” or “non-routable” (RFC 1918)?
- What is a VLAN?
- What is ARP and what is it used for?
- What is the difference between TCP and UDP?
- What is the purpose of a default gateway?
- What is command used to show the routing table on a Linux box?
- A TCP connection on a network can be uniquely defined by 4 things. What are those things?
- When a client running a web browser connects to a web server, what is the source port and what is the destination port of the connection?
- How do you add an IPv6 address to a specific interface?
- You have added an IPv4 and IPv6 address to interface eth0. A ping to the v4 address is working but a ping to the v6 address gives you the response
sendmsg: operation not permitted. What could be wrong? - What is SNAT and when should it be used?
- Explain how could you ssh login into a Linux system that DROPs all new incoming packets using a SSH tunnel.
- How do you stop a DDoS attack?
- How can you see content of an ip packet?
- What is IPoAC (RFC 1149)?
- What will happen when you bind port 0?
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