In this lesson,
we're going to cover network service ports and protocols.
Now, network service ports and protocols
are fundamental to the operation and management
of our modern networks.
These are different services that ensure
that network devices can discover each other,
communicate efficiently and relay important
system information to each other.
There are several key network services
that we're going to discuss,
including DNS, DHCP, SQL services, SNMP, and Syslog.
Each of these services does utilize different ports
that will help facilitate their operations
and to enable seamless network functionality
for all of our end users and clients.
First, let's talk about DNS.
Now, DNS, or the Domain Name System,
is just like the internet's phone book.
This system is used to translate human friendly domain names
like www.diontraining.com into an IP address that computers
can use to identify each other on a network.
Now, DNS is going to use port 53 by default,
and this is where DNS servers
are going to listen to requests from clients.
Now, the Domain Name System protocol is actually kind
of unique because it actually operates
on two different transport protocols, both TCP and UDP.
By default, it's going to use UDP for querying
and response messages that fit within a single packet.
If there's a larger message that needs to be sent,
then it's going to use TCP for those larger messages,
including things like zone transfers
between two different DNS servers.
Second, we have DHCP.
DHCP, or the Dynamic Host Configuration Protocol,
is used to automate the assignment of IP addresses,
subnet masks, gateways, and other networking parameters
to a client device.
This automation simplifies the process
of configuring devices on our IP networks.
These DHCP servers will typically listen
for client requests over port 67
using UDP as a transport mechanism,
and the DHCP clients will receive responses
back over port 68, again using UDP.
Third, we have SQL services.
Now, SQL services refers to the protocols
that are used by database servers
to manage, query and control operations
from the client applications that are requesting them.
Now, there isn't a single standard port
for all SQL services because different providers
who make different SQL servers
have chosen to use different port numbers.
But the two most common that you need to be aware
of are the Microsoft SQL Server and MySQL.
Microsoft's SQL Server will operate over port 1433,
and the MySQL server will operate over port 3306.
Now, these ports will allow for the management
of the databases and the retrieval of data
by authorized users and applications over these ports,
so keep that in mind.
The fourth one we have is known as SNMP.
Now, SNMP, or the Simple Network Management Protocol,
is used for collecting information
from and configuring different network devices like servers,
printers, hubs, switches, and routers over an IP network.
SNMP operates over two ports, which is port 161 and 162,
using the user datagram protocol.
Port 161 is used by SNMP managers
that are communicating with the SNMP agents
on the different devices to conduct polling.
Port 162 is used when agents want to send unsolicited
trap messages back to the SNMP manager,
which essentially is reporting information
back to the manager about that client device.
SNMP is crucial for network diagnostics
and performance monitoring,
and is something you'll use heavily
as a network administrator or network technician.
The fifth and final network service port
and protocol we need to discuss is syslog.
Now, syslog stands for system logging.
And the system logging protocol is a standard
for message logging that allows devices
to send event messages across IP networks
to an event message collector known as a syslog server.
These syslog servers will then store, process,
or forward the logs as needed,
based on the requirements you have.
Syslog operates over port 514,
using either UDP or TCP, depending on your use case.
If you want to use standard messaging and logging,
by default, it will use UDP over port 514.
But if you have a situation
where reliability becomes a concern,
you can configure it to use TCP over port 514 instead.
Alright, when it comes to network service ports
and protocols, I want you to remember
a couple of key things.
These ports and protocols
are crucial for the smooth functioning
of digital communications and network management.
Each one has a certain purpose that you need to be aware of.
DNS is used for resolving names to IP addresses
like a giant internet phone book,
and it does this over port 53.
DHCP is used for assigning network parameters
like the IP address, the subnet mask,
the gateway, and the DNS IPs for a given system,
and it does this using ports 67 and 68.
When it comes to SQL services, there are various ports used,
but the two you need to remember
is Microsoft's SQL Server operates on port 1433,
and MySQL server is going to operate over port 3306
to be able to do your database management and data querying.
When it comes to SNMP,
we're going to use this for network management,
and it operates over ports 161 and 162.
And finally, we have syslog that's used for event logging,
and this occurs over port 514, using UDP by default,
or TCP as a backup if reliability is a concern for you.