GCIH: GIAC Certified Incident HandlerDemo

Question

For what purpose would the following netcat command be used?

nc -V -W2 -z -p 53 192.168.193.33 21-112

A Configure host 192.168.193.33 to be a relay between two other systems
B Set up a backdoor on host 192.168.193.33 that listens on port 53
C Scan port 53 on 192.168.193.33 using a source port range of 21-112
D Send packets with a DNS payload ranging in size from 21-112 bytes to host 192.168.193.33
E Scan ports 21-112 on host 192.168.193.33 using source port of 53

Explanation

Netcat's zero-I/O mode (-z) checks for listening services without sending application data. A destination port argument in the form 21-112 specifies a port range to scan, and -p 53 binds the outbound connections to local source port 53. Therefore, it scans ports 21 through 112 on the target while using source port 53.

Learn more

OpenBSD nc(1) manual

GCIH: GIAC Certified Incident HandlerDemo

AstroTutor

Notes

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