Does Arp Happen First Or Dhcp

In most scenarios, DHCP will happen first. Here’s why: For a system to communicate with another over a network, it needs an IP Address. When a device is connected to a network, the DHCP process kicks off almost immediately. It will lease an IP Address to the device, along with other essential network settings like Subnet Mask, Default Gateway, and DNS Server information.

The role of ARP comes into play after the device has obtained an IP address from DHCP. The purpose of the ARP process is to map an IP address to the physical MAC address. For example, if your system now knows (courtesy of DHCP) that it needs to send a packet to a certain IP address (let’s say the Default Gateway), it doesn’t automatically know where exactly to send that packet. That’s when it invokes ARP to find out which machine owns that IP address, so it can use its MAC address for direct communication.

It’s important to note here that while this sequence (DHCP then ARP) applies to most cases, DHCP isn’t necessary for ARP to function. You could manually assign network configuration to each device entirely sidestepping DHCP, yet ARP would still be required for devices to converse within the subnet. Much like the characters in our networking drama, ARP and DHCP each have their distinct parts to play, yet how they perform together brings the story to life.

A good source to learn more about ARP and DHCP is GeeksforGeeks. It provides a detailed comparison between these two protocols, the steps involved in them, and how they function within a network environment.

For instance, you may find the following code snippets helpful,

For a DHCP request:

bootp client {
   hardware ethernet 00:a0:c9:14:c8:29;
   fixed-address 10.0.1.42;
}

And for an ARP broadcast message:

arp -a

This command will list all local MAC to IP address mappings that the ARP protocol has discovered or set up.ARP (Address Resolution Protocol) and DHCP (Dynamic Host Configuration Protocol) are both key to the successful operation of networks.

ARP is a protocol that’s used to find the associated physical address (MAC address) for an IP address on a local network. When a device wants to communicate with another device on the same network, it uses ARP to discover the corresponding MAC address. The process begins with an ARP Request packet that includes the known IP address, and ends when a device with the stated IP address responds with its MAC address.

Here’s an example: If Device A wants to send a message to Device B over the network, Device A sends out an ARP request with Device B’s IP address. Then Device B would reply back with its MAC address and from there, Device A will be able to complete the communication since it can uniquely identify Device B on the network.

Simple code to display arp table:

import os
os.system("arp -a")

DHCP, on the other hand, is responsible for automatically distributing necessary network configuration information (like IP addresses) to computers in a network. Without DHCP, a network administrator would need to manually assign these IP addresses to each computer or device in the network.

Understanding this, now let’s dive into your specific question: Does the ARP process happen first, or DHCP?

The answer is DHCP. When a device joins a network, the DHCP process initiates first. Before any network traffic can occur (and therefore, before any ARP communication can take place), the device needs an IP address. Thus, the device broadcasts a DHCP DISCOVERY packet over the network to locate the available DHCP servers. Those servers then respond with a DHCP OFFER packet that contains an available IP address. After receiving the offers, the device selects one and sends a DHCP REQUEST packet back to the chosen server, which finalizes the selection with a DHCP ACK (acknowledgement) packet.

After receiving its new IP address through DHCP, the device can then start exchanging ARP packets as needed to learn the MAC addresses of other devices on the network.

To sum up:

– DHCP happens first to give devices IP addresses.
– Once a device has an IP address, ARP can be used to translate IP addresses into MAC addresses for direct communication on the network.

For further reading:
About Arp visit Wikipedia
About Dhcp visit Wikipedia The Address Resolution Protocol (ARP) and the Dynamic Host Configuration Protocol (DHCP) both play critical roles in traditional layered network models. To understand whether ARP occurs first or DHCP, it’s key to delve into what each protocol does and how they interact within a network.

What does Address Resolution Protocol (ARP) do?

ARP is essentially a lookup tool for networks. It translates Internet Protocol (IP) addresses into physical Media Access Control (MAC) addresses. This conversion is necessary to facilitate communication between different systems on a shared network. The procedure for this is simple–once an IP packet destined for another device on the same network is at the data link layer set to be dispatched, instead of just sending it off blindly, the implementation does a quick check by broadcasting an ARP request packet to all devices on the LAN requesting the MAC address associated with the target IP. Whichever device owns the requested IP then recognizes its own IP in the ARP request and sends back an ARP response containing its MAC address.

Here’s a simple flow chart of how ARP works:

What does Dynamic Host Configuration Protocol (DHCP) do?

DHCP carries out something entirely disparate but equally crucial. It is a server-client protocol that automatically provides an Internet Protocol (IP) host with its IP address and other related configuration information such as the subnet mask and default gateway. In layman terms, DHCP assigns computers their identifying numbers and other details that enable networks to recognize them.

Does ARP Happen First Or DHCP?

Now that we understand both ARP and DHCP let’s dive into the discussion about which happens first.

To know why one protocol might run before the other, consider this typical scenario: a fresh-out-of-the-box computer connects to a network for the first time. It doesn’t have an assigned IP address yet, so it can’t fully partake in networking activities. This is where DHCP comes to the rescue.

Before the newly connected device communicates with any other devices, the hosts need to assign it an IP address. The DHCP comes into play by leasing an IP address to the device, which enables it to participate on the network later on. Once that’s done, that’s where ARP kicks in to map the IP address into a corresponding MAC address when communication is needed between the devices.

In code form, it would look something similar to this

// Example function for requesting an IP via DHCP
int dhcp_request_ip(dhcp_t *dhcp)
{
    // Implement logic for requesting IP and other configurations from DHCP
}

// Example function for resolving IP using ARP
int arp_resolve_ip(arp_t *arp)
{
    // Implement logic for resolving IP to MAC address
}

From the above explanation, we can imply that DHCP procedures must take place before ARP. Although there are exceptions in most aspects of computing, this ordering stands because a device must have an IP address before its MAC address can be paired with it—the fundamental purpose ARP serves.

This overall process improves operability, simplifies addressing, and enhances the smooth running of our beloved networks.

For more detailed study follow these links Understanding ARP and Understanding DHCP.When trying to understand the sequence of networking protocols during a device’s network connection setup, two protocols often arise: the Address Resolution Protocol (ARP) and the Dynamic Host Configuration Protocol (DHCP).

HTML:

The question is: Does ARP happen first or DHCP?

To answer this, let’s delve into the basics of these two crucial network protocols.

DHCP:

DHCP stands for Dynamic Host Configuration Protocol. It is utilized to assign IP addresses dynamically to network devices. In a local network setting, machines get their IP information from a server operating the DHCP protocol. For a device to initiate network communication, it must initially request an IP address from the available DHCP server(s). The process involves the following steps:

– The client sends a “DHCP Discover” message to initiate a network connection.
– Upon receiving this, the DHCP server sends back a “DHCP Offer” that contains feasible IP details for the client.
– The client then requests the suggested IP configuration via a “DHCP Request”
– The server finalizes the exchange by sending a “DHCP Ack”.

 
From the dhcp client end: sudo dhclient -v 

ARP:

Address Resolution Protocol (ARP), on the other hand, resolves known IP addresses to MAC (Media Access Control) addresses. Once a device has an IP, the ARP aids in linking that IP with the device’s physical MAC address, which is required for packet delivery over the network. This two-step process works as follows harvard.edu:

– The sender broadcasts an ARP request packet featuring the receiver’s IP address across the network.
– A response received from the device with the unmatched IP address reveals its MAC address; hence, the sender can update its ARP cache (a small memory chunk where IP to MAC resolutions get stored).

 
Display arp table: arp -a  

So what happens first – DHCP or ARP?

In reality, DHCP functions primarily. Remember, a device needs an IP address to initiate communications over a network. As previously noted, an IP address gets assigned by the DHCP.

The ARP comes next when the device desires to reach another device within the same network. The ARP assists in resolving the target device’s IP address into a MAC address, allowing for packet transmission to that specific device.

So succinctly put, the DHCP assigns the IP address first, and the ARP enables communication between devices by linking IPs to MAC addresses.

However, remember that the actual chain of events might differ based on the network in use. Some systems may have static IP assignments, bypassing the need for DHCP, but ARP remains a fundamental utility.

References:

• Harvard University Networking Article

Address Resolution Protocol (ARP) and Dynamic Host Configuration Protocol (DHCP) are both integral processes that enable network communication. However, they serve different roles and are utilized at varied points in the network communication process.

When a device connects to a network, it typically has to undergo DCHP first, then ARP. This is because DHCP is used for IP address assignment, which is needed before other network communications like ARP can take place.

DHCP: The Starting Point

When a new device joins a network, it will normally not have an IP address – or if it does, it may need a new one to function on this specific network. DHCP is responsible for managing the dynamic distribution of IP addresses within a network.

Here’s a simplified version of how DHCP works:

New Device: "Hello, I'm new here and I need an IP address to communicate."

DHCP Server: "Sure! Here's an IP address you can use. Also, here's subnet mask, default gateway, and DNS server info. You can use these for a while."

New Device: "Great, thank you!"

Considering that ARP needs to know the IP address of a device to proceed, DHCP must happen first to allocate that crucial piece of information.

ARP: Post-DHCP Step

Once a device has been assigned an IP address by DHCP, other devices in the network need to discover its physical (MAC) address to send it data over Ethernet or WiFi. This is where ARP comes into play.

Here’s how the ARP process unfolds:

Device A: "I have data for IP address X. Who has this?"

Device with IP X: "It's me, here is my MAC address."

Device A: "Thanks. Let's communicate."

ARP requests can’t be appropriately broadcast without the target IP address known in advance – the very detail provided via DHCP.

In Summary

In most cases, DHCP happens first so that the device receives an IP address. This identifier is important for subsequent ARP operations which map IP addresses to physical addresses on the network. Without DHCP, the ARP protocol wouldn’t know what IP address to search for in its communications.

For more detailed information about ARP and DHCP protocols, consider the documentation from Cisco Systems, a reputable source in networking technology.

Note that exceptions might exist in some network configurations, but generally speaking, the standard order of operation is as described: DHCP first, followed by ARP.The Address Resolution Protocol (ARP) and the Dynamic Host Configuration Protocol (DHCP) are both IP protocols used for different purposes in a network. Understanding the interaction between these two protocols can often be confusing, so let’s take an analytical approach to answer this question: Does ARP happen first, or DHCP?

How They Work Together

Well, on a new network where a client machine is booting up, the first protocol that kicks into action is the DHCP. A DHCP negotiation must happen first so that the client device can acquire a valid IP address from the DHCP server.

When a client machine boots up, it starts by sending a DHCP Discovery broadcast message looking for a DHCP server on the network. Because this is a broadcast message and the client doesn’t know the MAC address of any DHCP servers available on the network, the destination MAC address will be set to FF:FF:FF:FF:FF:FF (the broadcast address).

When the DHCP server receives this broadcast message, it responds with a DHCP Offer message. This message contains a proposed IP address for the client to use. The client acknowledges this offer by sending a DHCP Request message back to the server. Finally, the server sends a DHCP Acknowledge message back to the client, confirming that it can use the offered IP address.

Now let’s observe how the ARP fits in! Once the client device has acquired its IP address using DHCP, it can now proceed to communicate with other devices on the same network. It might need to know the physical address of another host (usually known as the MAC address) within the same subnet. And this is where ARP comes into play.

However, here’s the tricky part. The client machine only knows the destination IP address but doesn’t have the associated MAC address. ARP helps in this situation by linking the IP addresses to the corresponding MAC addresses. The client device would broadcast an ARP request over the network, asking “Who has this IP address?”. The device owning the requested IP address would respond with its MAC address, thus allowing communication to occur between the devices.

To see some practical examples, here is a source code representation of both DHCP transaction and ARP Request/Reply:

// DHCP Transaction
dhcp_discovery_msg = 'DHCPDISCOVER'
broadcast(dhcp_discovery_msg)
server_response = dhcp_offer_msg()
client_msg = dhcp_request_msg(server_response)
server_ack(client_msg)

// ARP Request and Reply
arp_request_msg = 'ARP REQUEST'
broadcast(arp_request_msg)
device_response = arp_reply_msg()

// Now we have the MAC address, we can directly communicate with the device.
communicate(device_response)

In summary, whether ARP happens first or DHCP, totally depends on the scenario. When a device initially joins a network, the DHCP protocol happens first to assign an IP address, then the ARP protocol comes into play when inter-device communication begins. Thus, both these protocols accomplish their own tasks and work hand-in-hand for smooth networking operations.

For more information about ARP and DHCP workings, consider reading the RFC 826 for ARP and RFC 2131 for DHCP.Under normal circumstances, the Dynamic Host Configuration Protocol (DHCP) discovers process happens before Address Resolution Protocol (ARP). Here’s an in-depth look at how DHCP and ARP operations typically unfold in a network environment:

DHCP Process

In a typical DHCP lease lifecycle, it includes the following operations:

–

DHCPDISCOVER

–

DHCPOFFER

–

DHCPREQUEST

–

DHCPACK

Step 1: DHCPDISCOVER

In the first step of the DHCP process, the device sends out a

DHCPDISCOVER

message to locate any available DHCP servers in the network. This is a broadcast packet that does not require an IP address.

Step 2: DHCPOFFER

When a DHCP server receives the

DHCPDISCOVER

message, it responds with a

DHCPOFFER

packet. This packet includes the IP address that the DHCP server has chosen for the device.

Step 3: DHCPREQUEST

Following the receipt of one or more

DHCPOFFER

messages, the client will respond to its preferred offer with a

DHCPREQUEST

message. The

DHCPREQUEST

essentially formalizes the client’s acceptance of the offered IP address.

Step 4: DHCPACK

Upon receiving the

DHCPREQUEST

message, the DHCP server sends a

DHCPACK

(Acknowledgement) message back to the device.

The above sequence is usually conducted before any communications can happen between devices on the same network. Once a device has an IP assigned via DHCP, it becomes addressable and available for communication.

ARP Process

Once DHCP completes its allocation processes, the ARP comes into play. The main operation of ARP is to resolve IPv4 addresses to physical MAC addresses. It contains two types – ARP request and ARP reply:

– A device sends an ARP request packet to find the MAC address of another device from which it only knows the IP address.
– If the device exists in the same network and is reachable, it sends back an ARP reply that contains its MAC address.

From the series of steps, it’s evident that DHCP occurs well before ARP; because, you need to have IP addresses before your host can engage ARP to map the IP addresses to their respective MAC addresses.

For source code implementation related to DHCP and ARP protocols, you might want to checkout various open-source libraries available on Github that handles these processes such as Infoblox Open’s DHCP library.

Remember, proper understanding of DHCP and ARP interactions forms the basis for effective troubleshooting of many network-related issues.The order in which ARP (Address Resolution Protocol) and DHCP (Dynamic Host Configuration Protocol) occur within a network environment can play an important role in network operations. And yes, the sequence matters.

Now, to answer the question if ARP happens before DHCP or not, it is essential to understand what both protocols do:

ARP

ARP is responsible for mapping IP network addresses to the hardware MAC (Media Access Control) addresses, allowing communication between devices within the same network. [Reference]

DHCP

On the other hand, DHCP dynamically assigns IP addresses to devices on a network, making IP address management considerably easier. [Reference]

Given this crucial information, we can now approach your original question.

Generally, DHCP sets the stage prior to ARP. Here’s why:

1. A device needs an IP address to communicate: When a device connects to a network, it doesn’t possess the necessary information to engage in fruitful communication—a key component of that being its own IP address. The device won’t be aware of its IP address until it has communicated with the DHCP server. Thus, DHCP needs to happen before any communication, including ARP, takes place.

2. Obtaining IP through DHCP DISCOVER message: Once connected to a network, a device broadcasts a DHCP DISCOVER message to find out available DHCP servers around. This inquiry is done through broadcasting because the device initially does not have any specific destination IP Address to send this request nor does it know of any existing DHCP Servers.

    ethernet.src_mac = my_mac_address
    ethernet.dst_mac = broadcast
    
    ip.src = 0.0.0.0
    ip.dst = 255.255.255.255
    
    udp.src_port = some_random_port
    udp.dst_port = 67

    dhcp.message_type = discover

Subsequently, a DHCP server picks up this broadcasted discover message, and replies with a DHCP OFFER message providing a ‘lease’ of a usable IP address to the newly joined device.

3. IP to MAC correlation via APR after having IP: Now having gained an IP address from DHCP, the device can now engage in network communications, needing ARP to determine the corresponding MAC addresses of other devices on the network using their known IPs.

Below table encapsulates this entire sequence:

In conclusion, before a device can begin communicating via ARP, it first needs to acquire its own unique IP address. As such, DHCP indeed comes into play prior to ARP in networking sequences.

A brief overview of the terms: DHCP (Dynamic Host Configuration Protocol) is a protocol used to assign dynamic IP addresses to devices on a network. It ensures that all devices have a unique IP in a network. An important part of DHCP is the concept of DHCP lease, which can be considered as the ‘lifespan’ or ‘validity period’ of an IP address.

On the other hand, ARP (Address Resolution Protocol) is another protocol employed by the Internet Protocol Suite. Its role is to map an IP address directly to a physical (MAC) address on the local network.

Does ARP happen first or DHCP?

In dealing with the question of priority between ARP and DHCP, it’s crucial to comprehend how these protocols function in different stages in the cycle of network interactions, particularly during the IP assignment and the data transfer stages:

This suggests that DHCP definitely precedes ARP in the context of a typical network connection setup process. You first need to obtain a valid IP address through DHCP before you can even start thinking about ARP requests/resolutions.

We can also illustrate with a simplified example. Consider that a new device enters the network and wants to get an IP from the DHCP server. This starts the DHCP four-step lease process:

1. DHCPDISCOVER

2. DHCPOFFER

3. DHCPREQUEST

4. DHCPACK

In these steps, there are no ARP requests because a broadcast message is being sent to the whole network. Only when the device has got its IP address and it needs to talk to some specific device (e.g., to access internet via the default gateway), ARP comes into play to resolve the targeted device’s MAC address:

arp -a <ip_address>

To sum it up, while both DHCP and ARP are essential components of network operations, their functions are invoked at different stages. DHCP, with its IP assignment role, generally happens prior to ARP, which is predominantly required for subsequent data transfers.

To further explore these concepts, you might find it useful to leverage packet sniffing tools such as Wireshark, enabling you to inspect various networking processes in real-time scenario.

As a professional coder, I often deal with the intricacies of network protocols like ARP (Address Resolution Protocol) and DHCP (Dynamic Host Configuration Protocol). A common question that arises is whether ARP takes precedence over DHCP, or vice-versa, and in what sequence they are executed.

ARP and DHCP perform essential tasks within a network. However, their functions differ remarkably; they interact but don’t directly relate to each other. Consequently, it’s not entirely accurate to say that one takes precedence or happens before the other but rather that they coexist to perform different roles during various stages of network communication.

Let’s delve a little deeper:

DHCP overview:
DHCP is primarily responsible for automatic IP addresses assignment as well as the distribution of other configuration parameters to devices on a network. [source] A new machine that joins a network will typically send out a DHCP discovery packet to get an IP address from the DHCP server. So, it doesn’t require knowledge of any device’s MAC address at this point.

ARP overview:
ARP, on the other hand, comes into play after the IP address assignment. Its primary role is translating IP addresses into MAC addresses [source]. Once a device knows the IP address of another device it wants to communicate with (maybe obtained through DHCP), it needs to find out the recipient’s MAC address before it can send data on the Ethernet (or Wi-Fi) network; and here, ARP kicks into action.

Considering these roles, you could infer that DHCP operations happen before ARP—but remember, this is context-specific to establishing a fresh network connection—both protocols run concurrently and apply where necessary throughout the lifespan of a networked device.

However, if we’re doing a case study analysis on how ARP takes precedence over DHCP, it might be looking at scenarios such as static IP addressing and ARP Poisoning.

For instance, in a manually configured (static) network, devices are assigned fixed IP addresses. Here, DHCP does not come into play at all. But even with static IP addresses, ARP is still used to map the IP addresses to MAC addresses when two devices need to communicate.

In an underhanded scenario like ARP Poisoning (Spoofing), an attacker sends false ARP messages to link their MAC address with the IP address of another device (usually the default gateway). Any data intended for that IP address will now be wrongly directed to the attacker’s machine. Despite having DHCP correctly assign IP addresses, an attacker can leverage ARP to disrupt a network’s communication.

So, while both ARP and DHCP are crucial to most network communications, certain circumstances demonstrate how one protocol – ARP, in this case, irrespective of DHCP’s function, can ‘take precedence’ in its effect. It must be emphasized that it doesn’t necessarily entail ARP executing before DHCP, but evidences potential situations where ARP can hold sway and create significant impact on network communication.

Here is some pseudo code illustrating this:

    
    // Device boots up
    // Sends DHCP request if necessary
    If not static IP: 
        send_DHCP_request()
        
    .....
    // Some time later, device wishes to send data to another IP
    mac_address = retrieve_MAC_from_ARP_cache(IP) 
    
    if not mac_address: // i.e., if MAC address of destination IP isn't known
        send_ARP_request(IP)
        
    .....
    // On receiving an ARP reply (hopefully), the device can now send a datagram
    send_datagram(mac_address, data)

This illustrative representation underscores their distinct roles within a networking context by demonstrating interaction without a strict ‘precedence’ principle.When discussing networking, especially within an IPv4 network setup, the sequence of events or rather timing is critically important. This of course, also applies to the relationship between the Address Resolution Protocol (ARP) and Dynamic Host Configuration Protocol (DHCP). Is it ARP or DHCP that springs into action first? To answer this question adequately, we need a clear understanding of what ARP and DHCP are, and their roles in networking.

DHCP and Its Role

The DHCP is like the HR department of a company, distributing IP address allocations to every device that joins the network. It hands out crucial details such as subnet mask information, default gateway, IP lease time, and DNS server. DHCP operates at layer 7 of the OSI model—the application layer.

Here is some sample code that could be used to configure a Linux machine to use DHCP to obtain its IP address:

# /etc/network/interfaces
auto eth0
iface eth0 inet dhcp

ARP and Its Role

On the other hand, ARP operates at layer 2—the data link layer—of the OSI model. When you think about ARP, think of it as the concierge desk in a hotel, directing everyone where to go. ARP essentially maps an IP address to a physical address on the local network, commonly called MAC Address. Without it, packets of data would not know how to find their destination within a local network.

For instance, here’s an example of a typical ARP table viewed on a Linux system:

$ arp -n
Address                  HWtype  HWaddress           Flags Mask            Iface
192.168.1.1              ether   00:18:39:6e:8a:ae   C                     eth0

So, What Happens First?

With our understanding of both, we can now tackle the primary question—does ARP happen first or DHCP?

Typically, DHCP comes before ARP.

When a device connects to a network, it basically has no knowledge of its environment. Consequently, the device needs to receive an IP address first before engaging with others. This is where DHCP marks its entrance. A DHCP discovery process initiates helping the client request for an IP address. If successful, DHCP provides the device with the necessary details including its unique IP address within that local network. Once the IP address is assigned to the client, other devices within the same local network will need to discover its MAC address by using ARP. The ultimate goal of this process is to successfully form a link between the device’s MAC address and the IP address it was given by the DHCP.

Practical Sequence Examples:

Let me illustrate this with an example. Suppose Client A wants to communicate with Client B in the same local network:

1. Client A makes a DHCP request to the DHCP server and gets an IP address.
2. Then, Client A wants to “talk” to Client B, but all it knows is Client B’s IP address, not its MAC address. Client A needs this MAC address because Ethernet communications use MAC addresses.
3. So, Client A broadcasts an ARP request across the network essentially asking ‘Who has this IP?’
4. Client B, having that IP, responds with an ARP reply containing its MAC address.
5. With that, Client A can finally establish direct communication with Client B.

Therefore, in summary, DHCP typically happens first to allocate the necessary IP addresses, and then ARP steps in to link these IP addresses to specific MAC addresses for data packet direction within an IPv4 network. Additionally, it’s worth mentioning that this process slightly varies when dealing with static IP address assignments or IPv6 networks, but that’s beyond the scope of this article.
Understanding the sequence in which ARP (Address Resolution Protocol) and DHCP (Dynamic Host Configuration Protocol) occur is essential to network operations and engineering. The question arises as to whether ARP happens first or DHCP.

Address Resolution Protocol (ARP)

ARP is responsible for mapping an IP address to a hardware address usually known as a MAC address on a local network. This straightforward process entails:

• An ARP request broadcasted across the network, containing the IP address of the target device.
• The device whose IP matches the one in the ARP request will send back an ARP reply, holding its MAC address.
• This enables devices to communicate on the same network even when only the IP address of the target device is known initially.

Dynamic Host Configuration Protocol (DHCP)

On the other hand, DHCP is a protocol used by network equipment to automatically assign IP addresses and other related network parameters to devices connected to the network. Its operation can basically be divided into four steps:

• DHCPDISCOVER: The client broadcasts a request for its configuration information.
• DHCPOFFER: The DHCP server replies with an IP address lease offer.
• DHCPREQUEST: The client agrees to the lease and requests it from the server.
• DHCPACK: The server acknowledges that it has granted the lease to the client.

Now, regarding which one comes first, it’s crucial to clarify that these are two separate protocols that operate at different layers of the OSI model and serve various purposes. However, in the context of a typical computer booting up and connecting to a network, DHCP usually comes before ARP.

The general flow goes like this: When your PC or another device boots up and connects to the network, it often doesn’t have an IP address yet. Without this, ARP wouldn’t know what to resolve. That’s when

DHCPDISCOVER

comes into play, where the device seeks an IP address assignment from the DHCP server. Once the device holds its IP through

DHCPACK

, ARP can further proceed to map this new IP address to the MAC address facilitating communication on the network.

So in answer to “Does Arp Happen First Or Dhcp”, it is generally DHCP that occurs before ARP within the context of a device starting up and acquiring network configurations. However, again note they’re separate protocols created for different tasks, and their usage depends heavily on the dedicated network architecture and the scenario when they are being used.

For additional insightful sources on the topic of ARP vs. DHCP, check out [Cisco’s networking documentation](https://www.cisco.com/c/en/us/support/docs/ip/dynamic-host-configuration-protocol-dhcp/27470-100.html) and the [RIPE NCC’s technical explainer on DHCP](https://learn-networking.com/network-design/how-does-arp-work-in-computer-networks).