How to Start IMAP POP3 Email Protocol Using NS3

To start Internet Message Access Protocol (IMAP) and Post Office Protocol version 3 (POP3) projects in NS3 which encompasses to replicate the email retrieval protocols’ behaviour in a network. Although NS3 doesn’t support built-in IMAP or POP3 executions directly, we can design these protocols to utilize custom applications or we replicate its behavior by existing NS3 aspects such as TCP-based interaction.

Let’s see how we can proceed:

Steps to Start IMAP POP3 Email Protocols Projects in NS3

Understand IMAP and POP3 Protocols

IMAP (RFC 3501):
- It permits users recovering the emails whereas storing them on the server.
- This protocol helps for folder management and partial downloads.
POP3 (RFC 1939):
- From the server to download emails and typically removes them later.
- We need to equate the simplified protocol to IMAP.
Common Features to Simulate:
- To launch a connection among an email client and server.
- We can swap commands and responses through TCP such as USER, PASS, STAT, LIST and RETR.
- To send email information like payload.

Set Up NS3

Install NS3:
- Go to nsnam.org to download and install NS3.
- We adhere to the installation instruction.
Verify Installation:

./waf –run scratch/test-example

Required Modules:
- internet: It supports for IP and TCP functionality.
- applications: For custom or bulk data applications.
- point-to-point or wifi: For the network topology, these modules are used.

Plan Your IMAP/POP3 Simulation

Topology:
- Basic client-server configuration: Node A (email client) ↔ Node B (email server).
- Optional: We can insert more clients or intermediate nodes for routing.
Simulation Goals:
- Utilize IMAP or POP3 to replicate the email retrieval.
- We want to estimate the performance indicators such as email retrieval time, throughput, and connection latency.

Create Custom IMAP/POP3 Applications

While NS3 doesn’t directly support built-in IMAP or POP3 applications, we can be replicated these protocols by means of making custom applications.

4.1 Steps to Create Custom Applications

Define IMAP/POP3 Client and Server Classes:
- We prolong the Application class making ImapClientApplication and Pop3ServerApplication.
Simulate Commands and Responses:
- Execute the simple command-response sequence for IMAP and POP3.
Handle TCP Connections:
- Launch and handle the TCP connections to utilize TCP sockets.
Transfer Data:
- Replicate the email retrieval like data payload transfer through TCP.

4.2 Example: Basic POP3 Client and Server

Following is a simple instance for a POP3 client-server application.

POP3 Server

#include “ns3/core-module.h”

#include “ns3/network-module.h”

#include “ns3/internet-module.h”

#include “ns3/applications-module.h”

using namespace ns3;

class Pop3Server : public Application {

public:

Pop3Server();

virtual ~Pop3Server();

void Setup(Address address);

private:

virtual void StartApplication();

virtual void StopApplication();

void HandleAccept(Ptr<Socket> socket, const Address& from);

void HandleRead(Ptr<Socket> socket);

Ptr<Socket> m_socket;

Address m_local;

std::list<Ptr<Socket>> m_socketList;

};

Pop3Server::Pop3Server() : m_socket(0) {}

Pop3Server::~Pop3Server() {

m_socket = 0;

}

void Pop3Server::Setup(Address address) {

m_local = address;

}

void Pop3Server::StartApplication() {

m_socket = Socket::CreateSocket(GetNode(), TcpSocketFactory::GetTypeId());

m_socket->Bind(m_local);

m_socket->Listen();

m_socket->SetAcceptCallback(

MakeNullCallback<bool, Ptr<Socket>, const Address&>(),

MakeCallback(&Pop3Server::HandleAccept, this));

}

void Pop3Server::StopApplication() {

while (!m_socketList.empty()) {

Ptr<Socket> acceptedSocket = m_socketList.front();

m_socketList.pop_front();

acceptedSocket->Close();

}

if (m_socket) {

m_socket->Close();

m_socket = 0;

}

void Pop3Server::HandleAccept(Ptr<Socket> socket, const Address& from) {

m_socketList.push_back(socket);

socket->SetRecvCallback(MakeCallback(&Pop3Server::HandleRead, this));

}

void Pop3Server::HandleRead(Ptr<Socket> socket) {

Ptr<Packet> packet;

Address from;

while ((packet = socket->RecvFrom(from))) {

// Process POP3 commands

uint8_t* buffer = new uint8_t[packet->GetSize()];

packet->CopyData(buffer, packet->GetSize());

std::string data = std::string((char*)buffer, packet->GetSize());

NS_LOG_INFO(“POP3 Server received: ” << data);

delete[] buffer;

// Send a simulated response

std::string response = “+OK Message retrieved\r\n”;

Ptr<Packet> responsePacket = Create<Packet>((uint8_t*)response.c_str(), response.length());

socket->Send(responsePacket);

}

POP3 Client

class Pop3Client : public Application {

public:

Pop3Client();

virtual ~Pop3Client();

void Setup(Address address);

private:

virtual void StartApplication();

virtual void StopApplication();

void Connect();

void HandleConnect(Ptr<Socket> socket);

void SendRequest();

void HandleRead(Ptr<Socket> socket);

Ptr<Socket> m_socket;

Address m_peer;

EventId m_sendEvent;

};

Pop3Client::Pop3Client() : m_socket(0) {}

Pop3Client::~Pop3Client() {

m_socket = 0;

}

void Pop3Client::Setup(Address address) {

m_peer = address;

}

void Pop3Client::StartApplication() {

m_socket = Socket::CreateSocket(GetNode(), TcpSocketFactory::GetTypeId());

m_socket->SetConnectCallback(

MakeCallback(&Pop3Client::HandleConnect, this),

MakeNullCallback<void, Ptr<Socket>>());

m_socket->SetRecvCallback(MakeCallback(&Pop3Client::HandleRead, this));

m_socket->Connect(m_peer);

}

void Pop3Client::StopApplication() {

if (m_socket) {

m_socket->Close();

m_socket = 0;

}

void Pop3Client::HandleConnect(Ptr<Socket> socket) {

NS_LOG_INFO(“POP3 Client connected to server.”);

SendRequest();

}

void Pop3Client::SendRequest() {

std::string request = “RETR 1\r\n”; // Simulated POP3 command

Ptr<Packet> packet = Create<Packet>((uint8_t*)request.c_str(), request.length());

m_socket->Send(packet);

}

void Pop3Client::HandleRead(Ptr<Socket> socket) {

Ptr<Packet> packet;

while ((packet = socket->Recv())) {

// Process server responses

uint8_t* buffer = new uint8_t[packet->GetSize()];

packet->CopyData(buffer, packet->GetSize());

std::string data = std::string((char*)buffer, packet->GetSize());

NS_LOG_INFO(“POP3 Client received: ” << data);

delete[] buffer;

}

Test and Debug

Enable Logging:

export NS_LOG=Pop3Client=level_all:Pop3Server=level_all

./waf –run scratch/pop3-simulation

Inspect Packet Flows:
- Examine the traffic within Wireshark to utilize PCAP tracing.

p2p.EnablePcapAll(“pop3”);

Verify Data Transmission:
- Confirm records making sure that commands like USER, PASS, LIST, RETR are properly swapped.

Evaluate Protocol Performance

Metrics to Measure:
- We estimate the performance metrics such as email retrieval time (latency), throughput, and connection reliability in diverse network conditions.
Use FlowMonitor:

FlowMonitorHelper flowMonitor;

Ptr<FlowMonitor> monitor = flowMonitor.InstallAll();

monitor->SerializeToXmlFile(“imap-pop3-performance.xml”, true, true);

Advanced Features

Simulate IMAP Behavior:

We execute the folder management and partial email downloads.
Prolong the command-response logic for IMAP-specific aspects such as SELECT, FETCH.

Multiple Clients/Servers:

Make a network including several email clients to recover data from one or more servers.

Simulate Network Conditions:

We insert the packet loss, delays, or bandwidth constraints to experiment protocol resilience.

Secure IMAP/POP3:

Replicate encrypted connections such as IMAPS/POP3S to utilize SSL/TLS.

In this setup, we understood the concept of IMAP POP3 Email Protocols Projects and their simulation and execution process to replicate and measure the performance in the simulation tool NS3. We will deliver additional valuable insights regarding this topic.

Receive customized support from phdprojects.org. We handle IMAP and POP3 implementations with a methodical approach, providing you with comprehensive explanations at each stage. For optimal project outcomes, you can rely on our experts, who will assist you throughout all phases of your IMAP and POP3 Email Protocols projects utilizing the NS3 tool.