This content originally appeared on DEV Community and was authored by Aisalkyn Aidarova
Network Protocols Explained for DevOps Engineers
1. What Is a Network Protocol?
A network protocol is a set of rules that defines how data is sent, received, and understood between devices on a network.
It ensures that computers, servers, routers, and switches can “speak the same language” — even if they use different hardware or software.
In DevOps, protocols are everywhere — from connecting to AWS EC2 via SSH, to delivering web apps through HTTP/HTTPS, to configuring DNS for domain routing.
2. Common Network Protocols and DevOps Use Cases
| Protocol | Full Form | DevOps Use Case | Port(s) | Example Command |
|---|---|---|---|---|
| HTTP / HTTPS | Hypertext Transfer Protocol (Secure) | Communication between browsers, APIs, and web servers | 80 / 443 | curl -I https://example.com |
| FTP / SFTP | File Transfer Protocol / Secure File Transfer Protocol | Transfer build artifacts, log files, or configs between servers | 21 / 22 | sftp user@server |
| SMTP / SMTPS | Simple Mail Transfer Protocol (Secure) | Send build notifications (e.g., Jenkins → Email) | 25 / 465 | Jenkins email plugin setup |
| DNS | Domain Name System | Maps domain names to IPs (e.g., myapp.devops.com → 52.31.12.4) |
53 | nslookup myapp.devops.com |
| DHCP | Dynamic Host Configuration Protocol | Automatically assigns IPs to instances in a subnet | 67 / 68 | AWS assigns IP automatically |
| SSH | Secure Shell | Secure remote login to EC2, Kubernetes nodes, and containers | 22 | ssh ec2-user@54.160.12.11 |
| TCP / IP | Transmission Control Protocol / Internet Protocol | Backbone of all internet and intranet communication | 0–65535 | Used by all major protocols |
| POP3 / IMAP | Post Office Protocol v3 / Internet Message Access Protocol | Retrieve Jenkins or monitoring system emails | 110 / 143 | Email client configuration |
| UDP | User Datagram Protocol | Used for DNS, video streaming, and real-time logs (fast, no error checking) | 53 / 67 / 123 | dig example.com |
| ARP | Address Resolution Protocol | Maps IP to MAC address inside LAN or VPC | N/A | arp -a |
| Telnet | Terminal Network Protocol | Legacy insecure protocol (replaced by SSH) | 23 | telnet host port |
| SNMP | Simple Network Management Protocol | Used by monitoring tools (e.g., Prometheus, Nagios) | 161 / 162 | Device metric collection |
| ICMP | Internet Control Message Protocol | Network diagnostics (ping, traceroute) |
N/A | ping google.com |
| NTP | Network Time Protocol | Synchronizes system clocks (used in AWS, logs, CI/CD) | 123 | timedatectl status |
| RIP / OSPF | Routing Information Protocol / Open Shortest Path First | Network routing between routers or VPCs | Dynamic | AWS route tables, routers |
3. Why Protocols Matter in DevOps
| DevOps Scenario | Protocols Involved | Explanation |
|---|---|---|
| Deploying a web app | HTTP/HTTPS, TCP/IP, DNS | HTTP routes traffic to your web server; DNS resolves the URL. |
| Accessing EC2 instances | SSH, TCP/IP | Secure shell login to configure or deploy. |
| Setting up Jenkins pipelines | HTTP (web UI), SMTP (email alerts), SSH (build agents) | Jenkins uses several protocols for full automation. |
| Monitoring and logging | SNMP, ICMP, NTP | Monitor health, ping servers, and sync time for log accuracy. |
| Container orchestration (Kubernetes) | TCP/IP, DNS, SSH | Pods communicate through internal DNS and TCP/IP. |
| File transfer between servers | SFTP / FTPS | Transfer configs, logs, or backups securely. |
| Load balancing and scaling | TCP, UDP, DNS | ALB routes user traffic evenly to multiple servers. |
4. 
Visual Summary (Whiteboard-Style Diagram)
+-------------------+
| User Browser |
| (HTTP/HTTPS) |
+-------------------+
|
v
+--------------------------+
| DNS resolves domain |
| (maps name → IP) |
+--------------------------+
|
v
+--------------------------+
| Load Balancer (TCP/IP) |
| Routes traffic to EC2s |
+--------------------------+
/ \
v v
+-------------------+ +-------------------+
| EC2 Web App | | EC2 Web App |
| (SSH for admin) | | (SFTP uploads) |
+-------------------+ +-------------------+
|
v
+--------------------------+
| Database (TCP/IP) |
| Time sync via NTP |
+--------------------------+
|
v
+--------------------------+
| Monitoring (SNMP/ICMP) |
+--------------------------+
5. Key Learning for DevOps Students
| Concept | What You’ll Do in Practice |
|---|---|
| Use SSH | Connect to EC2 and run commands securely |
| Understand DNS | Configure Route 53 or Ingress for your services |
| Use HTTP/HTTPS | Deploy and test web apps via Load Balancer |
| Work with TCP/IP | Debug connectivity and open/close ports |
| Use ICMP | Test connections with ping and traceroute
|
| Use NTP | Keep CI/CD logs and alerts time-synced |
| Secure with HTTPS / FTPS / SMTPS | Protect data in transit |
6. Real-Life Example: AWS Web App Flow
-
User enters
myapp.jump2tech.com. → DNS resolves it to ALB IP. - HTTP/HTTPS request hits ALB. → ALB forwards via TCP to EC2 backend.
- DevOps team accesses EC2 via SSH.
- EC2 syncs time via NTP, reports status via SNMP.
- Monitoring pings via ICMP.
- Logs and backups are sent via SFTP.
- Jenkins sends email alerts via SMTP.
This content originally appeared on DEV Community and was authored by Aisalkyn Aidarova