In REST APIs, HTTP verbs (methods) define the action to be performed on resources, while response codes indicate the outcome of those requests. Understanding both is essential for network automation and the CCNA exam.
The primary HTTP verbs used in network automation are:
**GET** - Retrieves data…In REST APIs, HTTP verbs (methods) define the action to be performed on resources, while response codes indicate the outcome of those requests. Understanding both is essential for network automation and the CCNA exam.
The primary HTTP verbs used in network automation are:
**GET** - Retrieves data from a server. Used to read configuration or status information from network devices. It should not modify any data.
**POST** - Creates new resources on the server. Used when adding new configurations, creating new objects, or submitting data to network controllers.
**PUT** - Updates or replaces an existing resource entirely. When modifying device configurations, PUT replaces the complete resource with new data.
**PATCH** - Partially updates an existing resource. Unlike PUT, PATCH only modifies specified fields rather than replacing the entire resource.
**DELETE** - Removes a resource from the server. Used to delete configurations or objects from network devices.
HTTP response codes are three-digit numbers indicating request status:
**2xx (Success):**
- 200 OK - Request succeeded
- 201 Created - New resource successfully created
- 204 No Content - Success but no data returned
**3xx (Redirection):**
- 301 Moved Permanently - Resource relocated
- 304 Not Modified - Cached version is current
**4xx (Client Errors):**
- 400 Bad Request - Malformed syntax
- 401 Unauthorized - Authentication required
- 403 Forbidden - Access denied
- 404 Not Found - Resource does not exist
**5xx (Server Errors):**
- 500 Internal Server Error - Generic server failure
- 503 Service Unavailable - Server temporarily overloaded
For network automation tasks, understanding these verbs and codes helps troubleshoot API interactions with platforms like Cisco DNA Center, Meraki Dashboard, or SD-WAN controllers. Proper interpretation ensures reliable automation scripts and effective network management.
HTTP Verbs and Response Codes - Complete CCNA Guide
Why HTTP Verbs and Response Codes Matter
In modern network automation and programmability, HTTP-based APIs (particularly REST APIs) are the primary method for managing network devices programmatically. Understanding HTTP verbs and response codes is essential for the CCNA exam because Cisco heavily emphasizes network automation skills. These concepts form the foundation of how applications communicate with network infrastructure through APIs.
What Are HTTP Verbs?
HTTP verbs (also called methods) define the type of action you want to perform on a resource. The most common verbs you need to know are:
GET - Retrieves data from a server. This is a read-only operation that does not modify any data. Example: Fetching the current interface configuration.
POST - Creates a new resource on the server. Example: Creating a new VLAN or adding a new user account.
PUT - Updates an existing resource by replacing it entirely. You must send the complete resource data. Example: Updating an entire interface configuration.
PATCH - Partially updates an existing resource. Only the fields being changed need to be sent. Example: Changing just the description of an interface.
DELETE - Removes a resource from the server. Example: Deleting a VLAN or removing an ACL entry.
What Are HTTP Response Codes?
Response codes are three-digit numbers returned by the server to indicate the result of a request. They are grouped into categories:
2xx (Success) - The request was successfully received and processed. - 200 OK - Standard success response, typically for GET requests - 201 Created - A new resource was successfully created (common with POST) - 204 No Content - Success, but no data to return (common with DELETE)
3xx (Redirection) - Further action needed to complete the request. - 301 Moved Permanently - Resource has been permanently relocated - 302 Found - Resource temporarily at a different location
4xx (Client Errors) - The request contains an error from the client side. - 400 Bad Request - Malformed syntax or invalid request - 401 Unauthorized - Authentication required or failed - 403 Forbidden - Server understood but refuses to authorize - 404 Not Found - Requested resource does not exist
5xx (Server Errors) - The server failed to fulfill a valid request. - 500 Internal Server Error - Generic server-side error - 503 Service Unavailable - Server temporarily unable to handle requests
How HTTP Communication Works
1. The client constructs an HTTP request with the appropriate verb 2. The request includes headers (authentication, content type) and optionally a body 3. The server processes the request and performs the action 4. The server returns a response code and any relevant data 5. The client interprets the response code to determine success or failure
Exam Tips: Answering Questions on HTTP Verbs and Response Codes
Tip 1: Remember the verb-action association: GET=Read, POST=Create, PUT=Replace, PATCH=Modify, DELETE=Remove. Create a mental acronym if helpful.
Tip 2: Know the difference between PUT and PATCH. PUT requires sending ALL data for a resource, while PATCH only requires the fields being changed.
Tip 3: Memorize key response codes by category. If you see a 4xx code, think client error. If you see 5xx, think server error.
Tip 4: Pay attention to scenario-based questions. If asked what verb to use when creating a new object, the answer is POST, not PUT.
Tip 5: Remember that 401 means authentication issues while 403 means you are authenticated but lack permission.
Tip 6: A 201 response specifically indicates something was created, while 200 is a general success. Match the response code to the operation type.
Tip 7: GET requests should never modify data on the server - they are safe and idempotent operations.
Tip 8: When troubleshooting API issues, response codes tell you where the problem lies - 4xx means fix your request, 5xx means the server has issues.