| AH |
Authentication Header |
|
|
Network Layer |
Learn more |
| ALPN |
Application Layer Protocol Negotiation |
|
|
Transport Layer |
TLS extention. |
| ARP |
Address Resolution Protocol |
|
|
Data Link Layer |
Learn more |
| BGP |
Border Gateway Protocol |
179 |
TCP |
Network Layer |
Learn more |
| DHCP |
Dynamic Host Configuration Protocol |
67, 68 |
|
Data Link Layer |
|
| DNS |
Domain Name System |
53 |
Mainly UDP, but can be TCP |
Application Layer |
Learn more. DNSSEC and DOH are enhancements. |
| EIGRP |
Enhanced Interior Gateway Routing Protocol |
|
|
Network Layer |
|
| ESP |
Encapsulating Security Payload |
|
|
Network Layer |
Learn more |
| HTTP |
Hyper Text Transfer Protocol |
80 |
TCP (QUIC for HTTP/3) |
Application Layer |
Learn more |
| HTTPS |
Hyper Text Transfer Protocol Secure |
443 |
TCP (QUIC for HTTP/3) |
Application Layer |
Learn more. Also called ‘HTTP over TLS (or SSL)’ |
| ICMP |
Internet Control Message Protocol |
|
|
Network Layer |
|
| IGRP |
Interior Gateway Routing Protocol |
|
|
Network Layer |
|
| IKE |
Internet Key Exchange |
500 (w/o NAT) & 4500 (with NAT) |
UDP |
Network Layer |
Learn more |
| IMAP |
Internet Message Access Protocol |
143 (insecure) & 993 (secure with TLS) |
TCP |
Application Layer |
Learn more |
| IP |
Internet Protocol |
|
|
Network Layer |
Learn more |
| IPSec |
Internet Protocol Security |
|
|
Network Layer |
Learn more |
| ISAKMP |
Internet Security Association and Key Management Protocol |
500 (w/o NAT) & 4500 (with NAT) |
UDP |
Network Layer |
Learn more |
| IS-IS |
Intermediate System To Intermediate System |
|
|
Network Layer |
|
| NAT |
Network Address Translation |
|
|
Network Layer |
|
| OCSP |
Online Certificate Status Protocol |
|
|
Transport Layer |
TLS extension. |
| OSPF |
Open Shortest Path First |
|
|
Network Layer |
|
| POP3 |
Post Office Protocol 3 |
110 (insecure) & 995 (secure with TLS) |
TCP |
Application Layer |
Learn more |
| RIP |
Routing Information Protocol |
|
|
Network Layer |
|
| SCP |
Secure Copy |
22 |
|
|
|
| SFTP |
Secure/SSH File Transfer Protocol |
22 |
|
|
SFTP vs FTPS vs TFTP, FTPS vs SFTP |
| SMTP |
Simple Mail Transfer Protocol |
25 (default, insecure), 2525 (insecure), 587 (secure with TLS) & 465 (deprecated, secure with TLS) |
TCP |
Application Layer |
Learn more |
| SNI |
Server Name Indication |
|
|
Transport Layer |
TLS extension. |
| SSH |
Secure Shell |
22 |
TCP |
Application Layer |
Learn more |
| SSL |
Secure Sockets Layer |
|
|
Transport Layer |
Almost replaced by TLS. |
| TCP |
Transmission Control Protocol |
|
- |
Transport Layer |
Learn more |
| TLS |
Transport Layer Security |
|
|
Transport Layer |
Learn more |
| UDP |
User Datagram Protocol |
|
- |
Transport Layer |
Learn more |