CV0-002 · Question #392
If a firewall only allows TCP/UPD traffic from ports under 25 and above 162, which of the following would be used for alerting purposes?
The correct answer is D. Syslog. Given a firewall rule that permits TCP/UDP traffic only on ports under 25 or above 162, the alerting system must use a port within these allowed ranges.
Question
If a firewall only allows TCP/UPD traffic from ports under 25 and above 162, which of the following would be used for alerting purposes?
Options
- ASNMP v3
- BSMTP
- CSNMP v1
- DSyslog
How the community answered
(31 responses)- A3% (1)
- B3% (1)
- C13% (4)
- D81% (25)
Why each option
Given a firewall rule that permits TCP/UDP traffic only on ports under 25 or above 162, the alerting system must use a port within these allowed ranges.
SNMP v3 uses UDP ports 161 (agent) and 162 (trap destination), neither of which are strictly under 25 nor strictly above 162, meaning they would be blocked by the firewall.
SMTP uses TCP port 25, which is not strictly under 25 nor strictly above 162, and therefore would be blocked by the firewall.
SNMP v1 uses UDP ports 161 (agent) and 162 (trap destination), neither of which are strictly under 25 nor strictly above 162, meaning they would be blocked by the firewall.
Syslog commonly uses UDP port 514, which falls into the firewall's allowed range of ports above 162, making it a viable protocol for sending alerts through this specific firewall configuration.
Concept tested: Firewall rules and common network service ports
Source: https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml
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