### Low-Level SNMPv3 GET Request with Privacy

Source: https://context7.com/lextudio/sharpsnmplib/llms.txt

For SNMPv3, use GetRequestMessage directly. This requires a prior engine discovery report and a privacy provider. This example uses SHA-256 authentication and AES-128 privacy.

```csharp
using System;
using System.Collections.Generic;
using System.Net;
using System.Threading.Tasks;
using Lextm.SharpSnmpLib;
using Lextm.SharpSnmpLib.Messaging;
using Lextm.SharpSnmpLib.Security;

var endpoint = new IPEndPoint(IPAddress.Parse("192.168.1.1"), 161);

// Step 1: Engine discovery
var discovery = Messenger.GetNextDiscovery(SnmpType.GetRequestPdu);
ISnmpMessage report = await discovery.GetResponseAsync(endpoint);

// Step 2: Build v3 GET with SHA-256 auth + AES-128 privacy
var auth = new SHA256AuthenticationProvider(new OctetString("authpassword"));
var priv = new AESPrivacyProvider(new OctetString("privpassword"), auth);

var variables = new List<Variable>
{
    new Variable(new ObjectIdentifier("1.3.6.1.2.1.1.1.0")), // sysDescr
};

var request = new GetRequestMessage(
    VersionCode.V3,
    Messenger.NextMessageId,
    Messenger.NextRequestId,
    new OctetString("myUser"),
    OctetString.Empty,   // contextName
    variables,
    priv,
    Messenger.MaxMessageSize,
    report);

ISnmpMessage response = await request.GetResponseAsync(endpoint);
var pdu = response.Pdu();
if (pdu.ErrorStatus.ToInt32() != 0)
    throw new Exception($"Error: {pdu.ErrorStatus}");

foreach (var v in pdu.Variables)
    Console.WriteLine($"{v.Id} = {v.Data}");
// 1.3.6.1.2.1.1.1.0 = Linux router 5.4.0
```

--------------------------------

### Install #SNMP Library via .NET CLI

Source: https://github.com/lextudio/sharpsnmplib/blob/master/readme.md

Use this command to add the #SNMP library package to your project using the .NET CLI.

```bash
dotnet add package Lextm.SharpSnmpLib
```

--------------------------------

### Synchronous SNMP GET (v1/v2c) with Messenger.Get

Source: https://context7.com/lextudio/sharpsnmplib/llms.txt

Use Messenger.Get for synchronous SNMP GET requests. Supports v1 and v2c only. The timeout parameter is in milliseconds (0 for infinite).

```csharp
using System;
using System.Collections.Generic;
using System.Net;
using Lextm.SharpSnmpLib;
using Lextm.SharpSnmpLib.Messaging;

var endpoint = new IPEndPoint(IPAddress.Parse("192.168.1.1"), 161);
var community = new OctetString("public");
var variables = new List<Variable>
{
    new Variable(new ObjectIdentifier("1.3.6.1.2.1.1.5.0")), // sysName
};

IList<Variable> result = Messenger.Get(VersionCode.V2, endpoint, community, variables, timeout: 3000);
Console.WriteLine($"System name: {result[0].Data}");
// System name: MyRouter
```

--------------------------------

### Messenger.Get — Synchronous SNMP GET (v1/v2c)

Source: https://context7.com/lextudio/sharpsnmplib/llms.txt

Synchronous variant of GET. The `timeout` parameter is in milliseconds (0 = infinite). Supports SNMP v1 and v2c only.

```APIDOC
## Messenger.Get — Synchronous SNMP GET (v1/v2c)

### Description
Synchronous variant of GET. The `timeout` parameter is in milliseconds (0 = infinite). Supports SNMP v1 and v2c only.

### Method
GET (Synchronous)

### Endpoint
N/A (Library method)

### Parameters
- **VersionCode**: `VersionCode` - The SNMP version (e.g., `VersionCode.V2`).
- **endpoint**: `IPEndPoint` - The network endpoint of the SNMP agent.
- **community**: `OctetString` - The community string for authentication.
- **variables**: `List<Variable>` - A list of `Variable` objects representing the OIDs to retrieve.
- **timeout**: `int` - Timeout in milliseconds (0 for infinite).

### Request Example
```csharp
using System;
using System.Collections.Generic;
using System.Net;
using Lextm.SharpSnmpLib;
using Lextm.SharpSnmpLib.Messaging;

var endpoint = new IPEndPoint(IPAddress.Parse("192.168.1.1"), 161);
var community = new OctetString("public");
var variables = new List<Variable>
{
    new Variable(new ObjectIdentifier("1.3.6.1.2.1.1.5.0")), // sysName
};

IList<Variable> result = Messenger.Get(VersionCode.V2, endpoint, community, variables, timeout: 3000);
Console.WriteLine($"System name: {result[0].Data}");
```

### Response
#### Success Response
- **IList<Variable>**: A list of `Variable` objects containing the retrieved OID values.

#### Response Example
```
System name: MyRouter
```
```

--------------------------------

### Install #SNMP Library via NuGet Package Manager

Source: https://github.com/lextudio/sharpsnmplib/blob/master/readme.md

Use this command to add the #SNMP library package to your project using the NuGet Package Manager in Visual Studio.

```powershell
Install-Package Lextm.SharpSnmpLib
```

--------------------------------

### Discover SNMP Agents on the Network with Discoverer

Source: https://context7.com/lextudio/sharpsnmplib/llms.txt

Broadcasts a GET request to discover SNMP agents. Subscribe to AgentFound and ExceptionRaised events before calling DiscoverAsync. Discovery targets UDP port 161.

```csharp
using System;
using System.Net;
using System.Threading.Tasks;
using Lextm.SharpSnmpLib;
using Lextm.SharpSnmpLib.Messaging;

var discoverer = new Discoverer();

discoverer.AgentFound += (sender, args) =>
{
    Console.WriteLine($"Found agent at {args.Agent}");
    if (args.Variable != null)
        Console.WriteLine($"  sysDescr: {args.Variable.Data}");
};

discoverer.ExceptionRaised += (sender, args) =>
{
    Console.WriteLine($"Discovery error: {args.Exception.Message}");
};

// Broadcast to 255.255.255.255:161 for 2 seconds
var broadcastEndpoint = new IPEndPoint(IPAddress.Broadcast, 161);
await discoverer.DiscoverAsync(VersionCode.V2, broadcastEndpoint, new OctetString("public"), interval: 2000);

Console.WriteLine("Discovery complete.");
// Found agent at 192.168.1.1:161
//   sysDescr: Cisco IOS Software
```

--------------------------------

### Discoverer - Discover SNMP Agents

Source: https://context7.com/lextudio/sharpsnmplib/llms.txt

Broadcasts a GET request to discover SNMP agents on the network. Subscribe to AgentFound and ExceptionRaised events before calling Discover or DiscoverAsync.

```APIDOC
## Discoverer

### Description
Broadcasts a GET request over UDP to discover SNMP agents in a subnet. Subscribe to `AgentFound` and `ExceptionRaised` events before calling `Discover` or `DiscoverAsync`.

### Usage Example
```csharp
using System;
using System.Net;
using System.Threading.Tasks;
using Lextm.SharpSnmpLib;
using Lextm.SharpSnmpLib.Messaging;

var discoverer = new Discoverer();

discoverer.AgentFound += (sender, args) =>
{
    Console.WriteLine($"Found agent at {args.Agent}");
    if (args.Variable != null)
        Console.WriteLine($"  sysDescr: {args.Variable.Data}");
};

discoverer.ExceptionRaised += (sender, args) =>
{
    Console.WriteLine($"Discovery error: {args.Exception.Message}");
};

// Broadcast to 255.255.255.255:161 for 2 seconds
var broadcastEndpoint = new IPEndPoint(IPAddress.Broadcast, 161);
await discoverer.DiscoverAsync(VersionCode.V2, broadcastEndpoint, new OctetString("public"), interval: 2000);

Console.WriteLine("Discovery complete.");
```

### Events
- **AgentFound**: Event triggered when an SNMP agent is found.
- **ExceptionRaised**: Event triggered when an exception occurs during discovery.
```

--------------------------------

### Send SNMP v2c INFORM Request

Source: https://context7.com/lextudio/sharpsnmplib/llms.txt

Use Messenger.SendInformAsync for acknowledged traps. This example shows a v2c INFORM request, which does not require a privacy provider or report message.

```csharp
using System;
using System.Collections.Generic;
using System.Net;
using System.Threading.Tasks;
using Lextm.SharpSnmpLib;
using Lextm.SharpSnmpLib.Messaging;
using Lextm.SharpSnmpLib.Security;

var receiver = new IPEndPoint(IPAddress.Parse("192.168.1.100"), 162);
var community = new OctetString("public");
var enterprise = new ObjectIdentifier("1.3.6.1.4.1.99999.2");
uint timestamp = 11111;

var variables = new List<Variable>
{
    new Variable(new ObjectIdentifier("1.3.6.1.2.1.1.5.0"), new OctetString("InformDevice")),
};

// v2c INFORM — no privacy provider or report required
await Messenger.SendInformAsync(
    requestId: Messenger.NextRequestId,
    VersionCode.V2,
    receiver,
    community,
    OctetString.Empty,    // contextName
    enterprise,
    timestamp,
    variables,
    privacy: null,        // null for v2c
    report: null);        // null for v2c

Console.WriteLine("INFORM sent and acknowledged.");
```

--------------------------------

### Create SNMP Variable Bindings for GET and SET Operations

Source: https://context7.com/lextudio/sharpsnmplib/llms.txt

Represents an SNMP variable binding, pairing an ObjectIdentifier with an ISnmpData value. Used in GET, SET, Walk, and Trap operations. Supports read-only (Null data) and writeable variables with typed SNMP data.

```csharp
using System;
using Lextm.SharpSnmpLib;

// Read-only variable (for GET requests — Data defaults to Null)
var getVar = new Variable(new ObjectIdentifier("1.3.6.1.2.1.1.1.0"));
Console.WriteLine(getVar); // Variable: Id: 1.3.6.1.2.1.1.1.0; Data: Null

// Write variable (for SET requests)
var setVar = new Variable(
    new ObjectIdentifier("1.3.6.1.2.1.1.5.0"),
    new OctetString("NewHostName"));
Console.WriteLine(setVar.Id);    // 1.3.6.1.2.1.1.5.0
Console.WriteLine(setVar.Data);  // NewHostName

// Using typed SNMP data
var counterVar = new Variable(
    new ObjectIdentifier("1.3.6.1.2.1.2.2.1.10.1"), // ifInOctets.1
    new Counter32(1048576));

var gaugeVar = new Variable(
    new ObjectIdentifier("1.3.6.1.2.1.2.2.1.5.1"), // ifSpeed.1
    new Gauge32(1000000000)); // 1 Gbps

var timeVar = new Variable(
    new ObjectIdentifier("1.3.6.1.2.1.1.3.0"), // sysUpTime
    new TimeTicks(123456));

Console.WriteLine($"Counter: {counterVar.Data}"); // 1048576
Console.WriteLine($"Speed: {gaugeVar.Data}");     // 1000000000
Console.WriteLine($"Uptime: {timeVar.Data}");     // 123456
```

--------------------------------

### Messenger.GetAsync — Asynchronous SNMP GET (v1/v2c)

Source: https://context7.com/lextudio/sharpsnmplib/llms.txt

Sends an asynchronous GET request to retrieve one or more OID variable bindings from an SNMP agent. Supports SNMP v1 and v2c. Throws `ErrorException` if the agent returns an error status.

```APIDOC
## Messenger.GetAsync — Asynchronous SNMP GET (v1/v2c)

### Description
Sends a GET request to retrieve one or more OID variable bindings from an SNMP agent. Supports SNMP v1 and v2c. Throws `ErrorException` if the agent returns an error status.

### Method
GET (Asynchronous)

### Endpoint
N/A (Library method)

### Parameters
- **VersionCode**: `VersionCode` - The SNMP version (e.g., `VersionCode.V2`).
- **endpoint**: `IPEndPoint` - The network endpoint of the SNMP agent.
- **community**: `OctetString` - The community string for authentication.
- **variables**: `List<Variable>` - A list of `Variable` objects representing the OIDs to retrieve.

### Request Example
```csharp
using System;
using System.Collections.Generic;
using System.Net;
using System.Threading.Tasks;
using Lextm.SharpSnmpLib;
using Lextm.SharpSnmpLib.Messaging;

var endpoint = new IPEndPoint(IPAddress.Parse("192.168.1.1"), 161);
var community = new OctetString("public");
var variables = new List<Variable>
{
    new Variable(new ObjectIdentifier("1.3.6.1.2.1.1.1.0")), // sysDescr
    new Variable(new ObjectIdentifier("1.3.6.1.2.1.1.3.0")), // sysUpTime
};

try
{
    IList<Variable> result = await Messenger.GetAsync(VersionCode.V2, endpoint, community, variables);
    foreach (var v in result)
    {
        Console.WriteLine($"OID: {v.Id}  Value: {v.Data}");
    }
}
catch (ErrorException ex)
{
    Console.WriteLine($"SNMP error: {ex.Message}");
}
catch (TimeoutException ex)
{
    Console.WriteLine($"Timeout: {ex.Message}");
}
```

### Response
#### Success Response
- **IList<Variable>**: A list of `Variable` objects containing the retrieved OID values.

#### Response Example
```
OID: 1.3.6.1.2.1.1.1.0  Value: Linux router 5.4.0
OID: 1.3.6.1.2.1.1.3.0  Value: 123456
```
```

--------------------------------

### GetRequestMessage

Source: https://context7.com/lextudio/sharpsnmplib/llms.txt

Provides low-level access for constructing and sending SNMPv3 GET requests, requiring engine discovery, a privacy provider, and a report message.

```APIDOC
## GetRequestMessage — Low-Level SNMPv3 GET

For SNMPv3, use `GetRequestMessage` directly with a privacy provider and a prior engine-discovery report message.

### Method
`GetRequestMessage` constructor and `GetResponseAsync` method.

### Parameters
- `version` (VersionCode): The SNMP version (V3).
- `messageId` (int): The unique message ID.
- `requestId` (int): The unique request ID.
- `userName` (OctetString): The username for authentication.
- `contextName` (OctetString): The context name.
- `variables` (List<Variable>): A list of variables to retrieve.
- `privacy` (IPrivacyProvider): The privacy provider.
- `maxMessageSize` (int): The maximum message size.
- `report` (ISnmpMessage): The report message from engine discovery.

### Request Example
```csharp
// Step 1: Engine discovery
var discovery = Messenger.GetNextDiscovery(SnmpType.GetRequestPdu);
ISnmpMessage report = await discovery.GetResponseAsync(endpoint);

// Step 2: Build v3 GET with SHA-256 auth + AES-128 privacy
var auth = new SHA256AuthenticationProvider(new OctetString("authpassword"));
var priv = new AESPrivacyProvider(new OctetString("privpassword"), auth);

var variables = new List<Variable>
{
    new Variable(new ObjectIdentifier("1.3.6.1.2.1.1.1.0")), // sysDescr
};

var request = new GetRequestMessage(
    VersionCode.V3,
    Messenger.NextMessageId,
    Messenger.NextRequestId,
    new OctetString("myUser"),
    OctetString.Empty,   // contextName
    variables,
    priv,
    Messenger.MaxMessageSize,
    report);

ISnmpMessage response = await request.GetResponseAsync(endpoint);
```

### Response
- `ISnmpMessage`: The SNMP response message.
- The PDU of the response contains `ErrorStatus` and `Variables`.
```

--------------------------------

### Asynchronous SNMP GET (v1/v2c) with Messenger.GetAsync

Source: https://context7.com/lextudio/sharpsnmplib/llms.txt

Use Messenger.GetAsync to retrieve SNMP variables asynchronously. Supports v1 and v2c. Handles ErrorException and TimeoutException.

```csharp
using System;
using System.Collections.Generic;
using System.Net;
using System.Threading.Tasks;
using Lextm.SharpSnmpLib;
using Lextm.SharpSnmpLib.Messaging;

var endpoint = new IPEndPoint(IPAddress.Parse("192.168.1.1"), 161);
var community = new OctetString("public");
var variables = new List<Variable>
{
    new Variable(new ObjectIdentifier("1.3.6.1.2.1.1.1.0")), // sysDescr
    new Variable(new ObjectIdentifier("1.3.6.1.2.1.1.3.0")), // sysUpTime
};

try
{
    IList<Variable> result = await Messenger.GetAsync(VersionCode.V2, endpoint, community, variables);
    foreach (var v in result)
    {
        Console.WriteLine($"OID: {v.Id}  Value: {v.Data}");
    }
    // OID: 1.3.6.1.2.1.1.1.0  Value: Linux router 5.4.0
    // OID: 1.3.6.1.2.1.1.3.0  Value: 123456
}
catch (ErrorException ex)
{
    Console.WriteLine($"SNMP error: {ex.Message}");
}
catch (TimeoutException ex)
{
    Console.WriteLine($"Timeout: {ex.Message}");
}
```

--------------------------------

### Asynchronous SNMP Bulk Walk (GET-BULK, v2c/v3) with Messenger.BulkWalkAsync

Source: https://context7.com/lextudio/sharpsnmplib/llms.txt

Walks an OID subtree using GET-BULK requests for efficiency with large tables. Supports v2c and v3. maxRepetitions controls variables per request. Requires contextName and privacy/report parameters for v3.

```csharp
using System;
using System.Collections.Generic;
using System.Net;
using System.Threading.Tasks;
using Lextm.SharpSnmpLib;
using Lextm.SharpSnmpLib.Messaging;
using Lextm.SharpSnmpLib.Security;

var endpoint = new IPEndPoint(IPAddress.Parse("192.168.1.1"), 161);
var community = new OctetString("public");
var tableOid = new ObjectIdentifier("1.3.6.1.2.1.2.2"); // ifTable
var results = new List<Variable>();

int rowCount = await Messenger.BulkWalkAsync(
    VersionCode.V2,
    endpoint,
    community,
    OctetString.Empty,       // contextName (empty for v2c)
    tableOid,
    results,
    maxRepetitions: 10,
    WalkMode.WithinSubtree,
    privacy: null,           // null for v2c
    report: null);           // null for v2c

Console.WriteLine($"Interface table rows: {rowCount}");
// Interface table rows: 4
```

--------------------------------

### Asynchronous SNMP Walk (GET-NEXT, v1/v2c) with Messenger.WalkAsync

Source: https://context7.com/lextudio/sharpsnmplib/llms.txt

Walks an OID subtree using GET-NEXT requests. Returns the number of rows if the OID is a table. Use WalkMode.WithinSubtree to stop at the subtree boundary.

```csharp
using System;
using System.Collections.Generic;
using System.Net;
using System.Threading.Tasks;
using Lextm.SharpSnmpLib;
using Lextm.SharpSnmpLib.Messaging;

var endpoint = new IPEndPoint(IPAddress.Parse("192.168.1.1"), 161);
var community = new OctetString("public");
// Walk the interfaces table (IF-MIB::ifTable)
var tableOid = new ObjectIdentifier("1.3.6.1.2.1.2.2");
var results = new List<Variable>();

int rowCount = await Messenger.WalkAsync(
    VersionCode.V2,
    endpoint,
    community,
    tableOid,
    results,
    WalkMode.WithinSubtree);

Console.WriteLine($"Rows found: {rowCount}, Total variables: {results.Count}");
foreach (var v in results)
{
    Console.WriteLine($"  {v.Id} = {v.Data}");
}
// Rows found: 3, Total variables: 33
//   1.3.6.1.2.1.2.2.1.1.1 = 1
//   1.3.6.1.2.1.2.2.1.2.1 = eth0
//   ...
```

--------------------------------

### Messenger.BulkWalkAsync

Source: https://context7.com/lextudio/sharpsnmplib/llms.txt

Performs an asynchronous SNMP Bulk Walk (GET-BULK) for more efficient retrieval of large tables. Supports SNMPv2c and v3.

```APIDOC
## Messenger.BulkWalkAsync — Asynchronous SNMP Bulk Walk (GET-BULK, v2c/v3)

Walks an OID subtree using GET-BULK requests, which is more efficient for large tables. Supports v2c and v3. `maxRepetitions` controls how many variables are returned per GET-BULK request.

### Method
`Task<int> BulkWalkAsync(VersionCode version, EndPoint endpoint, OctetString community, OctetString contextName, ObjectIdentifier oid, IList<Variable> variables, int maxRepetitions, WalkMode walkMode, ISnmpMessage privacy, ISnmpMessage report)`

### Parameters
- **version** (VersionCode) - The SNMP version to use (v2c or v3).
- **endpoint** (EndPoint) - The network endpoint of the SNMP agent.
- **community** (OctetString) - The community string for authentication (for v2c).
- **contextName** (OctetString) - The context name for SNMPv3.
- **oid** (ObjectIdentifier) - The starting Object Identifier for the walk.
- **variables** (IList<Variable>) - A list to store the retrieved variables.
- **maxRepetitions** (int) - The maximum number of repetitions per GET-BULK request.
- **walkMode** (WalkMode) - Specifies how the walk should proceed (e.g., `WalkMode.WithinSubtree`).
- **privacy** (ISnmpMessage) - Privacy parameters for SNMPv3 (null for v2c).
- **report** (ISnmpMessage) - Report parameters for SNMPv3 (null for v2c).

### Request Example
```csharp
using System.Net;
using Lextm.SharpSnmpLib;
using Lextm.SharpSnmpLib.Messaging;

var endpoint = new IPEndPoint(IPAddress.Parse("192.168.1.1"), 161);
var community = new OctetString("public");
var tableOid = new ObjectIdentifier("1.3.6.1.2.1.2.2"); // ifTable
var results = new List<Variable>();

int rowCount = await Messenger.BulkWalkAsync(
    VersionCode.V2,
    endpoint,
    community,
    OctetString.Empty,       // contextName (empty for v2c)
    tableOid,
    results,
    maxRepetitions: 10,
    WalkMode.WithinSubtree,
    privacy: null,           // null for v2c
    report: null);           // null for v2c

Console.WriteLine($"Interface table rows: {rowCount}");
```

### Response
#### Success Response
Returns the number of rows found. The `results` list will be populated with `Variable` objects.

#### Response Example
```
Interface table rows: 4
```
```

--------------------------------

### Configure SNMPv3 User Registry with Authentication and Privacy

Source: https://context7.com/lextudio/sharpsnmplib/llms.txt

Maps SNMPv3 usernames to IPrivacyProvider for authentication and encryption. Pass the registry to MessageFactory.ParseMessages or low-level message constructors. Supports multiple users with different security protocols.

```csharp
using Lextm.SharpSnmpLib;
using Lextm.SharpSnmpLib.Security;

// Build a registry for an SNMPv3 agent that supports multiple users
var registry = new UserRegistry(new[]
{
    // User 1: SHA-256 authentication, AES-128 privacy
    new User(
        new OctetString("adminUser"),
        new AESPrivacyProvider(
            new OctetString("privPassword1"),
            new SHA256AuthenticationProvider(new OctetString("authPassword1")))),

    // User 2: MD5 authentication, DES privacy
    new User(
        new OctetString("readUser"),
        new DESPrivacyProvider(
            new OctetString("privPassword2"),
            new MD5AuthenticationProvider(new OctetString("authPassword2")))),

    // User 3: SHA-1 authentication, no privacy
    new User(
        new OctetString("monitorUser"),
        new DefaultPrivacyProvider(
            new SHA1AuthenticationProvider(new OctetString("authPassword3")))),
});

Console.WriteLine(registry); // User registry: count: 3

// Look up a user at message-receive time
IPrivacyProvider? provider = registry.Find(new OctetString("adminUser"));
Console.WriteLine(provider); // AES 128 privacy provider
```

--------------------------------

### Messenger.WalkAsync

Source: https://context7.com/lextudio/sharpsnmplib/llms.txt

Performs an asynchronous SNMP Walk (GET-NEXT) to traverse an OID subtree. It returns the number of rows found, which is particularly useful when walking tables.

```APIDOC
## Messenger.WalkAsync — Asynchronous SNMP Walk (GET-NEXT, v1/v2c)

Walks an OID subtree using GET-NEXT requests. Returns the number of rows if the OID is a table; otherwise this value is not meaningful. Use `WalkMode.WithinSubtree` to stop at the subtree boundary.

### Method
`Task<int> WalkAsync(VersionCode version, EndPoint endpoint, OctetString community, ObjectIdentifier oid, IList<Variable> variables, WalkMode walkMode)`

### Parameters
- **version** (VersionCode) - The SNMP version to use (v1 or v2c).
- **endpoint** (EndPoint) - The network endpoint of the SNMP agent.
- **community** (OctetString) - The community string for authentication.
- **oid** (ObjectIdentifier) - The starting Object Identifier for the walk.
- **variables** (IList<Variable>) - A list to store the retrieved variables.
- **walkMode** (WalkMode) - Specifies how the walk should proceed (e.g., `WalkMode.WithinSubtree`).

### Request Example
```csharp
using System.Net;
using Lextm.SharpSnmpLib;
using Lextm.SharpSnmpLib.Messaging;

var endpoint = new IPEndPoint(IPAddress.Parse("192.168.1.1"), 161);
var community = new OctetString("public");
var tableOid = new ObjectIdentifier("1.3.6.1.2.1.2.2"); // IF-MIB::ifTable
var results = new List<Variable>();

int rowCount = await Messenger.WalkAsync(
    VersionCode.V2,
    endpoint,
    community,
    tableOid,
    results,
    WalkMode.WithinSubtree);

Console.WriteLine($"Rows found: {rowCount}, Total variables: {results.Count}");
```

### Response
#### Success Response
Returns the number of rows found. The `results` list will be populated with `Variable` objects.

#### Response Example
```
Rows found: 3, Total variables: 33
  1.3.6.1.2.1.2.2.1.1.1 = 1
  1.3.6.1.2.1.2.2.1.2.1 = eth0
```
```

--------------------------------

### Asynchronous SNMP SET (v1/v2c) with Messenger.SetAsync

Source: https://context7.com/lextudio/sharpsnmplib/llms.txt

Use Messenger.SetAsync to modify SNMP variable values asynchronously. Supports v1 and v2c. Throws ErrorException on agent-reported errors.

```csharp
using System;
using System.Collections.Generic;
using System.Net;
using System.Threading.Tasks;
using Lextm.SharpSnmpLib;
using Lextm.SharpSnmpLib.Messaging;

var endpoint = new IPEndPoint(IPAddress.Parse("192.168.1.1"), 161);
var community = new OctetString("private");

// Set sysName (1.3.6.1.2.1.1.5.0) to "NewRouterName"
var variables = new List<Variable>
{
    new Variable(new ObjectIdentifier("1.3.6.1.2.1.1.5.0"), new OctetString("NewRouterName")),
};

try
{
    IList<Variable> result = await Messenger.SetAsync(VersionCode.V2, endpoint, community, variables);
    Console.WriteLine($"SET succeeded. Returned: {result[0].Data}");
    // SET succeeded. Returned: NewRouterName
}
catch (ErrorException ex)
{
    Console.WriteLine($"SET failed: {ex.Message}");
}
```

--------------------------------

### Construct and Convert SNMP Object Identifiers (OIDs)

Source: https://context7.com/lextudio/sharpsnmplib/llms.txt

Represents SNMP OIDs and supports construction from dotted-decimal strings or uint arrays. Enables comparison operators and serialization. OIDs can be extended to represent table entries.

```csharp
using System;
using Lextm.SharpSnmpLib;

// From dotted string
var oidFromString = new ObjectIdentifier("1.3.6.1.2.1.1.1.0");
Console.WriteLine(oidFromString); // 1.3.6.1.2.1.1.1.0

// From uint array
var oidFromArray = new ObjectIdentifier(new uint[] { 1, 3, 6, 1, 2, 1, 1, 5, 0 });
Console.WriteLine(oidFromArray); // 1.3.6.1.2.1.1.5.0

// Comparison
var a = new ObjectIdentifier("1.3.6.1.2.1.1.1.0");
var b = new ObjectIdentifier("1.3.6.1.2.1.1.2.0");
Console.WriteLine(a < b);  // True
Console.WriteLine(a == b); // False

// Extend an OID (e.g., table row index)
var tableEntry = new ObjectIdentifier("1.3.6.1.2.1.2.2.1.2");
var withIndex = ObjectIdentifier.Create(tableEntry.ToNumerical(), 1);
Console.WriteLine(withIndex); // 1.3.6.1.2.1.2.2.1.2.1

// Convert between string and uint[]
uint[] numerical = ObjectIdentifier.Convert("1.3.6.1.4.1.99999");
string dotted = ObjectIdentifier.Convert(numerical);
Console.WriteLine(dotted); // 1.3.6.1.4.1.99999
```

--------------------------------

### ObjectIdentifier - OID Construction and Conversion

Source: https://context7.com/lextudio/sharpsnmplib/llms.txt

Represents an SNMP Object Identifier (OID), supporting construction from strings or arrays, comparison, and conversion.

```APIDOC
## ObjectIdentifier

### Description
`ObjectIdentifier` represents an SNMP OID. It can be constructed from a dotted-decimal string or a `uint[]` array, and supports comparison operators and serialization.

### Usage Example
```csharp
using System;
using Lextm.SharpSnmpLib;

// From dotted string
var oidFromString = new ObjectIdentifier("1.3.6.1.2.1.1.1.0");
Console.WriteLine(oidFromString); // 1.3.6.1.2.1.1.1.0

// From uint array
var oidFromArray = new ObjectIdentifier(new uint[] { 1, 3, 6, 1, 2, 1, 1, 5, 0 });
Console.WriteLine(oidFromArray); // 1.3.6.1.2.1.1.5.0

// Comparison
var a = new ObjectIdentifier("1.3.6.1.2.1.1.1.0");
var b = new ObjectIdentifier("1.3.6.1.2.1.1.2.0");
Console.WriteLine(a < b);  // True
Console.WriteLine(a == b); // False

// Extend an OID (e.g., table row index)
var tableEntry = new ObjectIdentifier("1.3.6.1.2.1.2.2.1.2");
var withIndex = ObjectIdentifier.Create(tableEntry.ToNumerical(), 1);
Console.WriteLine(withIndex); // 1.3.6.1.2.1.2.2.1.2.1

// Convert between string and uint[]
uint[] numerical = ObjectIdentifier.Convert("1.3.6.1.4.1.99999");
string dotted = ObjectIdentifier.Convert(numerical);
Console.WriteLine(dotted); // 1.3.6.1.4.1.99999
```

### Methods
- **Create(uint[] numerical, params uint[] suffix)**: Creates a new `ObjectIdentifier` by extending an existing numerical OID.
- **Convert(string oid)**: Converts a dotted-decimal OID string to a `uint[]` array.
- **Convert(uint[] numerical)**: Converts a `uint[]` array to a dotted-decimal OID string.
```

--------------------------------

### Send SNMPv2c Trap with Messenger.SendTrapV2Async

Source: https://context7.com/lextudio/sharpsnmplib/llms.txt

Sends a TRAP v2c message to a trap receiver. Only VersionCode.V2 is supported. Enterprise OID and timestamp are embedded in the varbind structure. Requires request ID, receiver, community, enterprise OID, timestamp, and variables.

```csharp
using System;
using System.Collections.Generic;
using System.Net;
using System.Threading.Tasks;
using Lextm.SharpSnmpLib;
using Lextm.SharpSnmpLib.Messaging;

var receiver = new IPEndPoint(IPAddress.Parse("192.168.1.100"), 162);
var community = new OctetString("public");
var enterprise = new ObjectIdentifier("1.3.6.1.4.1.99999.1");
uint timestamp = 67890;

var variables = new List<Variable>
{
    new Variable(new ObjectIdentifier("1.3.6.1.2.1.1.5.0"), new OctetString("AlertDevice")),
};

await Messenger.SendTrapV2Async(
    requestId: Messenger.NextRequestId,
    VersionCode.V2,
    receiver,
    community,
    enterprise,
    timestamp,
    variables);

Console.WriteLine("SNMPv2c trap sent.");
```

--------------------------------

### Parse Raw SNMP Bytes with MessageFactory

Source: https://context7.com/lextudio/sharpsnmplib/llms.txt

Use MessageFactory.ParseMessages to decode raw UDP byte buffers into ISnmpMessage objects. A UserRegistry is required for v3 decryption, which should contain known users and their security providers.

```csharp
using System;
using System.Collections.Generic;
using Lextm.SharpSnmpLib;
using Lextm.SharpSnmpLib.Messaging;
using Lextm.SharpSnmpLib.Security;

// Simulate receiving raw bytes from a UDP socket
byte[] rawBytes = /* ... bytes from UdpClient.Receive() ... */ Array.Empty<byte>();

// For v1/v2c, an empty registry is sufficient
var registry = new UserRegistry();

// For v3, add known users:
// var auth = new SHA1AuthenticationProvider(new OctetString("authphrase"));
// var priv = new AESPrivacyProvider(new OctetString("privphrase"), auth);
// registry.Add(new OctetString("myUser"), priv);

try
{
    IList<ISnmpMessage> messages = MessageFactory.ParseMessages(rawBytes, registry);
    foreach (var msg in messages)
    {
        Console.WriteLine($"Type: {msg.TypeCode()}  Version: {msg.Version}");
        foreach (var v in msg.Variables())
            Console.WriteLine($"  {v.Id} = {v.Data}");
    }
}
catch (SnmpException ex)
{
    Console.WriteLine($"Parse error: {ex.Message}");
}
```

--------------------------------

### Messenger.SendInformAsync

Source: https://context7.com/lextudio/sharpsnmplib/llms.txt

Sends an acknowledged INFORM request, supporting both v2c and v3 protocols. For v3, a privacy provider and a prior report message are required.

```APIDOC
## Messenger.SendInformAsync — Send INFORM Request (v2c/v3)

Sends an INFORM request, which is an acknowledged trap. Supports v2c and v3. For v3, a valid privacy provider and a prior report message (from engine discovery) must be provided.

### Method
`SendInformAsync`

### Parameters
- `requestId` (int): The unique identifier for the request.
- `version` (VersionCode): The SNMP version (V2 or V3).
- `receiver` (IPEndPoint): The endpoint of the receiver.
- `community` (OctetString): The community string for authentication.
- `contextName` (OctetString): The context name for v3.
- `enterprise` (ObjectIdentifier): The enterprise OID.
- `timestamp` (uint): The timestamp for the PDU.
- `variables` (List<Variable>): A list of variables to send.
- `privacy` (IPrivacyProvider): The privacy provider for v3.
- `report` (ISnmpMessage): The report message for v3.

### Request Example (v2c)
```csharp
await Messenger.SendInformAsync(
    requestId: Messenger.NextRequestId,
    VersionCode.V2,
    receiver,
    community,
    OctetString.Empty,    // contextName
    enterprise,
    timestamp,
    variables,
    privacy: null,        // null for v2c
    report: null);        // null for v2c
```

### Response
Indicates success if the INFORM request is acknowledged.
```

--------------------------------

### Messenger.SetAsync — Asynchronous SNMP SET (v1/v2c)

Source: https://context7.com/lextudio/sharpsnmplib/llms.txt

Sends an asynchronous SET request to write one or more OID values on an SNMP agent. Supports v1 and v2c. Throws `ErrorException` on agent-reported errors.

```APIDOC
## Messenger.SetAsync — Asynchronous SNMP SET (v1/v2c)

### Description
Sends a SET request to write one or more OID values on an SNMP agent. Supports v1 and v2c. Throws `ErrorException` on agent-reported errors.

### Method
SET (Asynchronous)

### Endpoint
N/A (Library method)

### Parameters
- **VersionCode**: `VersionCode` - The SNMP version (e.g., `VersionCode.V2`).
- **endpoint**: `IPEndPoint` - The network endpoint of the SNMP agent.
- **community**: `OctetString` - The community string for authentication.
- **variables**: `List<Variable>` - A list of `Variable` objects representing the OIDs and their new values.

### Request Example
```csharp
using System;
using System.Collections.Generic;
using System.Net;
using System.Threading.Tasks;
using Lextm.SharpSnmpLib;
using Lextm.SharpSnmpLib.Messaging;

var endpoint = new IPEndPoint(IPAddress.Parse("192.168.1.1"), 161);
var community = new OctetString("private");

// Set sysName (1.3.6.1.2.1.1.5.0) to "NewRouterName"
var variables = new List<Variable>
{
    new Variable(new ObjectIdentifier("1.3.6.1.2.1.1.5.0"), new OctetString("NewRouterName")),
};

try
{
    IList<Variable> result = await Messenger.SetAsync(VersionCode.V2, endpoint, community, variables);
    Console.WriteLine($"SET succeeded. Returned: {result[0].Data}");
}
catch (ErrorException ex)
{
    Console.WriteLine($"SET failed: {ex.Message}");
}
```

### Response
#### Success Response
- **IList<Variable>**: A list of `Variable` objects containing the values returned by the agent after the SET operation.

#### Response Example
```
SET succeeded. Returned: NewRouterName
```
```

--------------------------------

### UserRegistry - SNMPv3 User Store

Source: https://context7.com/lextudio/sharpsnmplib/llms.txt

Manages SNMPv3 usernames and their associated privacy providers (authentication and encryption). Used in message parsing and construction.

```APIDOC
## UserRegistry

### Description
`UserRegistry` maps SNMPv3 usernames to their `IPrivacyProvider` (which bundles authentication + encryption). It is passed to `MessageFactory.ParseMessages` and to low-level message constructors.

### Usage Example
```csharp
using Lextm.SharpSnmpLib;
using Lextm.SharpSnmpLib.Security;

// Build a registry for an SNMPv3 agent that supports multiple users
var registry = new UserRegistry(new[]
{
    // User 1: SHA-256 authentication, AES-128 privacy
    new User(
        new OctetString("adminUser"),
        new AESPrivacyProvider(
            new OctetString("privPassword1"),
            new SHA256AuthenticationProvider(new OctetString("authPassword1")))),

    // User 2: MD5 authentication, DES privacy
    new User(
        new OctetString("readUser"),
        new DESPrivacyProvider(
            new OctetString("privPassword2"),
            new MD5AuthenticationProvider(new OctetString("authPassword2")))),

    // User 3: SHA-1 authentication, no privacy
    new User(
        new OctetString("monitorUser"),
        new DefaultPrivacyProvider(
            new SHA1AuthenticationProvider(new OctetString("authPassword3")))),
});

Console.WriteLine(registry); // User registry: count: 3

// Look up a user at message-receive time
IPrivacyProvider? provider = registry.Find(new OctetString("adminUser"));
Console.WriteLine(provider); // AES 128 privacy provider
```

### Methods
- **Find(OctetString username)**: Looks up and returns the `IPrivacyProvider` for the given username.
```

--------------------------------

### Send SNMPv1 Trap with Messenger.SendTrapV1Async

Source: https://context7.com/lextudio/sharpsnmplib/llms.txt

Sends a TRAP v1 message to a trap receiver, typically listening on UDP port 162. Requires receiver endpoint, agent address, community, enterprise OID, trap type, specific code, timestamp, and variables.

```csharp
using System;
using System.Collections.Generic;
using System.Net;
using System.Threading.Tasks;
using Lextm.SharpSnmpLib;
using Lextm.SharpSnmpLib.Messaging;

var receiver = new IPEndPoint(IPAddress.Parse("192.168.1.100"), 162);
var agentAddress = IPAddress.Parse("192.168.1.1");
var community = new OctetString("public");
var enterprise = new ObjectIdentifier("1.3.6.1.4.1.99999");
uint timestamp = 12345;

var variables = new List<Variable>
{
    new Variable(new ObjectIdentifier("1.3.6.1.2.1.1.5.0"), new OctetString("AlertRouter")),
};

await Messenger.SendTrapV1Async(
    receiver,
    agentAddress,
    community,
    enterprise,
    GenericCode.ColdStart,
    specific: 0,
    timestamp,
    variables);

Console.WriteLine("SNMPv1 trap sent.");
```

--------------------------------

### MessageFactory.ParseMessages

Source: https://context7.com/lextudio/sharpsnmplib/llms.txt

Parses raw SNMP byte buffers into ISnmpMessage objects, essential for SNMP agents and trap listeners. Requires a UserRegistry for v3 decryption.

```APIDOC
## MessageFactory.ParseMessages — Parse Raw SNMP Bytes

Parses one or more raw UDP byte buffers into `ISnmpMessage` objects. Used by SNMP agents or trap listeners to decode incoming packets. A `UserRegistry` must be provided for v3 decryption.

### Method
`ParseMessages`

### Parameters
- `rawBytes` (byte[]): The raw byte buffer received from a UDP socket.
- `registry` (UserRegistry): A registry of users for v3 decryption. Can be empty for v1/v2c.

### Request Example
```csharp
// Simulate receiving raw bytes from a UDP socket
byte[] rawBytes = /* ... bytes from UdpClient.Receive() ... */ Array.Empty<byte>();

// For v1/v2c, an empty registry is sufficient
var registry = new UserRegistry();

// For v3, add known users:
// var auth = new SHA1AuthenticationProvider(new OctetString("authphrase"));
// var priv = new AESPrivacyProvider(new OctetString("privphrase"), auth);
// registry.Add(new OctetString("myUser"), priv);

try
{
    IList<ISnmpMessage> messages = MessageFactory.ParseMessages(rawBytes, registry);
    foreach (var msg in messages)
    {
        Console.WriteLine($"Type: {msg.TypeCode()}  Version: {msg.Version}");
        foreach (var v in msg.Variables())
            Console.WriteLine($"  {v.Id} = {v.Data}");
    }
}
catch (SnmpException ex)
{
    Console.WriteLine($"Parse error: {ex.Message}");
}
```

### Response
- `IList<ISnmpMessage>`: A list of parsed SNMP messages.
- Throws `SnmpException` if parsing fails.
```