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In this lesson,

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we're going to cover network service ports and protocols.

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Now, network service ports and protocols

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are fundamental to the operation and management

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of our modern networks.

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These are different services that ensure

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that network devices can discover each other,

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communicate efficiently and relay important

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system information to each other.

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There are several key network services

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that we're going to discuss,

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including DNS, DHCP, SQL services, SNMP, and Syslog.

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Each of these services does utilize different ports

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that will help facilitate their operations

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and to enable seamless network functionality

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for all of our end users and clients.

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First, let's talk about DNS.

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Now, DNS, or the Domain Name System,

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is just like the internet's phone book.

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This system is used to translate human friendly domain names

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like www.diontraining.com into an IP address that computers

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can use to identify each other on a network.

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Now, DNS is going to use port 53 by default,

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and this is where DNS servers

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are going to listen to requests from clients.

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Now, the Domain Name System protocol is actually kind

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of unique because it actually operates

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on two different transport protocols, both TCP and UDP.

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By default, it's going to use UDP for querying

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and response messages that fit within a single packet.

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If there's a larger message that needs to be sent,

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then it's going to use TCP for those larger messages,

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including things like zone transfers

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between two different DNS servers.

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Second, we have DHCP.

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DHCP, or the Dynamic Host Configuration Protocol,

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is used to automate the assignment of IP addresses,

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subnet masks, gateways, and other networking parameters

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to a client device.

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This automation simplifies the process

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of configuring devices on our IP networks.

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These DHCP servers will typically listen

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for client requests over port 67

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using UDP as a transport mechanism,

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and the DHCP clients will receive responses

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back over port 68, again using UDP.

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Third, we have SQL services.

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Now, SQL services refers to the protocols

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that are used by database servers

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to manage, query and control operations

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from the client applications that are requesting them.

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Now, there isn't a single standard port

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for all SQL services because different providers

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who make different SQL servers

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have chosen to use different port numbers.

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But the two most common that you need to be aware

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of are the Microsoft SQL Server and MySQL.

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Microsoft's SQL Server will operate over port 1433,

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and the MySQL server will operate over port 3306.

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Now, these ports will allow for the management

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of the databases and the retrieval of data

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by authorized users and applications over these ports,

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so keep that in mind.

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The fourth one we have is known as SNMP.

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Now, SNMP, or the Simple Network Management Protocol,

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is used for collecting information

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from and configuring different network devices like servers,

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printers, hubs, switches, and routers over an IP network.

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SNMP operates over two ports, which is port 161 and 162,

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using the user datagram protocol.

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Port 161 is used by SNMP managers

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that are communicating with the SNMP agents

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on the different devices to conduct polling.

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Port 162 is used when agents want to send unsolicited

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trap messages back to the SNMP manager,

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which essentially is reporting information

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back to the manager about that client device.

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SNMP is crucial for network diagnostics

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and performance monitoring,

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and is something you'll use heavily

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as a network administrator or network technician.

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The fifth and final network service port

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and protocol we need to discuss is syslog.

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Now, syslog stands for system logging.

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And the system logging protocol is a standard

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for message logging that allows devices

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to send event messages across IP networks

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to an event message collector known as a syslog server.

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These syslog servers will then store, process,

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or forward the logs as needed,

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based on the requirements you have.

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Syslog operates over port 514,

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using either UDP or TCP, depending on your use case.

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If you want to use standard messaging and logging,

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by default, it will use UDP over port 514.

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But if you have a situation

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where reliability becomes a concern,

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you can configure it to use TCP over port 514 instead.

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Alright, when it comes to network service ports

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and protocols, I want you to remember

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a couple of key things.

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These ports and protocols

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are crucial for the smooth functioning

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of digital communications and network management.

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Each one has a certain purpose that you need to be aware of.

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DNS is used for resolving names to IP addresses

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like a giant internet phone book,

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and it does this over port 53.

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DHCP is used for assigning network parameters

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like the IP address, the subnet mask,

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the gateway, and the DNS IPs for a given system,

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and it does this using ports 67 and 68.

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When it comes to SQL services, there are various ports used,

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but the two you need to remember

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is Microsoft's SQL Server operates on port 1433,

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and MySQL server is going to operate over port 3306

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to be able to do your database management and data querying.

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When it comes to SNMP,

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we're going to use this for network management,

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and it operates over ports 161 and 162.

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And finally, we have syslog that's used for event logging,

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and this occurs over port 514, using UDP by default,

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or TCP as a backup if reliability is a concern for you.