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Network+ Exam

Network Service Ports and Protocols

October 29, 2025

  • #network+

Network Service Ports and Protocols

Different services that ensure that network devices can discover each other communicat efficently and relya importan system information to each other.

DNS: Domain name system, used to translate human-friendly domaninnames to an IP address that computers can use to find a computer. uses PORT 53. uses TCP,large message and UDP, small messages

DHCP : Dynamic Host Configuration Protool DHCP- used to automate the assignment of ip addresses, submets, mass gateways, and otehr networking paramerers to a client device. listen for client requetst to port 67 and the clients will receive on port 86

SQL Services - Protocols used by database servers to manae queries an control operati0ons from the client applicaton sthat are requeting them. Microsoft SQL - 1433 MY SQL 3306 can manage

sSNMP -simple network management protocol. Used for collection information from and configureing diffent network devices like servers, hubs, printers, routers 161 and 162. used by SNMP managers port 162

Syslog - Stanard for message logging that allows devices to send event messages adcros IP networks to an event message collector known as a syslog server. port 514 using UDP or TCP.

needed for the managmt fo the network

DNS 53 phone book

DHCP - IP ADDRESSES 67 / 68

SQL port 1433/ port 3306 database mamane

SNMP 161/162

syslog port 514 for system logs.

Network Service Ports & Protocols (High-Yield)

Services that let devices discover each other, communicate efficiently, and exchange essential system info.

1. DNS – Domain Name System

  • Purpose: Translates human-friendly domain names → IP addresses.
  • Ports:
    • 53 TCP → large queries (e.g., zone transfers)
    • 53 UDP → small queries (most lookups)
  • Exam Tip: Think of DNS as the phonebook of the internet.

2. DHCP – Dynamic Host Configuration Protocol

  • Purpose: Automatically assigns IP addresses, subnet masks, default gateways, and DNS info to clients.
  • Ports:
    • 67 UDP → server listens (requests from client)
    • 68 UDP → client listens (responses from server)
  • Exam Tip: DHCP DISCOVER → OFFER → REQUEST → ACK (DORA process).

3. SQL Services

  • Purpose: Manage database queries and operations between client apps and database servers.
  • Common Ports:
    • 1433 TCP → Microsoft SQL Server
    • 3306 TCP → MySQL
  • Must Know: Often targeted in attacks (SQL injection).

4. SNMP – Simple Network Management Protocol

  • Purpose: Monitors and configures network devices (routers, switches, printers).
  • Ports:
    • 161 UDP → manager queries agents
    • 162 UDP → agents send traps to manager
  • Versions: v1, v2c (community strings), v3 (secure with encryption/authentication).

5. Syslog

  • Purpose: Standard for sending event/log messages across IP networks to a central log server.
  • Ports:
    • 514 UDP/TCP
  • Use: Network monitoring & SIEM integration.

Quick Port Reference Table

| Service | Port(s) | Protocol | Notes | | --- | --- | --- | --- | | DNS | 53 TCP/UDP | Name resolution | TCP for large queries, UDP for normal | | DHCP | 67/68 UDP | IP config automation | DORA process | | Microsoft SQL | 1433 TCP | Database | Server-based DB | | MySQL | 3306 TCP | Database | Open-source DB | | SNMP | 161/162 UDP | Network mgmt | v3 = secure | | Syslog | 514 UDP/TCP | Log collection | Centralized logging |

Memory Trick:

"Do Data Services So Smartly" → DNS (53), DHCP (67/68), SQL (1433/3306), SNMP (161/162), Syslog (514)