Network Protocols and the OSI Model
2 min read
There are various network protocols and they work at different layers of the OSI model. The diagram below gives a quick reference of protocols and the layers at which they work. There are more than these protocols but we have just mentioned the common ones.
Advice is to have an understanding of these protocols.
Networking Devices
| Hub | Multiport repeater, Half Duplex, No intelligence, connect Devices together |
|---|---|
| Switch | Forward traffic to right destination |
| Router | Route Tables, forwarding based on IP Table , connected multiple type of networks |
| Access Point | Wireless router or WAP , Bridge to connect, wired or wireless |
| DSL | |
| Repeater | Regenerates signals |
| FireWall | Filters traffic , routers or dedicated hardware |
| Bridge | |
| Patch Panels | |
| CloudBased network controller | Central way to |
| EOP ethernet over power lines | |
| Power over ethernet |
Most Used common protocols
| Scenario | Protocol | Ports | Details | |
|---|---|---|---|---|
| Files | FTP | 20/21 | ||
| AFP | 548 | |||
| SMB | TCP | 445 | ||
| Emails | SMTP | 25 | 25 | |
| POP3 | 110 | |||
| IMAP | 143 | |||
| Web | HTTPS | 443 | ||
| HTTP | 80 | |||
| Management | Telnet | 23 | ||
| SSH | 22 | |||
| SNMP | TCP/UDP | 161/162 | ||
| RDP | 3389 | |||
| DNS | 53 | |||
| DHCP | 67/68 | |||
| SLP(Service Location Protocol) | 427 | |||
| NetBios | TCP/UDP | 137/138/139 | ||
| LDAP( Lightweight Directory Access Protocol) | TCP/UDP | 389 | ||
| Network time Protocol | ||||
| ARP( Address Resolution Protocol) |