Common TCP & UDP Ports
Well-known port numbers for network services.
Well-known ports (0-1023) identify the standard services that run on networked hosts. This table covers the ports you will actually use when configuring firewalls, ACLs, and services: SSH, DNS, HTTP and HTTPS, mail, NTP, DHCP, SNMP, and the database and remote-access ports.
Use it as a quick lookup when writing firewall rules - the Firewall Rules template pairs well with this table.
| Port | Proto | Service | Description |
|---|---|---|---|
| 20 | TCP | FTP Data | File Transfer Protocol (data channel) |
| 21 | TCP | FTP Control | File Transfer Protocol (control) |
| 22 | TCP | SSH | Secure Shell |
| 23 | TCP | Telnet | Unencrypted remote access (avoid) |
| 25 | TCP | SMTP | Mail transfer between servers |
| 53 | UDP/TCP | DNS | Domain Name System |
| 67/68 | UDP | DHCP | Dynamic Host Configuration Protocol |
| 80 | TCP | HTTP | Hypertext Transfer Protocol |
| 110 | TCP | POP3 | Post Office Protocol v3 |
| 123 | UDP | NTP | Network Time Protocol |
| 143 | TCP | IMAP | Internet Message Access Protocol |
| 161/162 | UDP | SNMP | Simple Network Management Protocol |
| 389 | TCP | LDAP | Lightweight Directory Access Protocol |
| 443 | TCP | HTTPS | HTTP over TLS/SSL |
| 514 | UDP | Syslog | System logging |
| 587 | TCP | SMTP | Mail submission (authenticated) |
| 636 | TCP | LDAPS | LDAP over TLS/SSL |
| 993 | TCP | IMAPS | IMAP over TLS/SSL |
| 995 | TCP | POP3S | POP3 over TLS/SSL |
| 1194 | UDP | OpenVPN | OpenVPN default port |
| 1812/1813 | UDP | RADIUS | Authentication & accounting |
| 3389 | TCP | RDP | Remote Desktop Protocol |
| 5432 | TCP | PostgreSQL | PostgreSQL database |
| 8080 | TCP | HTTP Alt | HTTP alternative / proxy |
| 8443 | TCP | HTTPS Alt | HTTPS alternative |
More Reference
Explore the other reference in the toolkit.
RFC 1918 Private IP Ranges
RFC 1918 defines the private IPv4 ranges 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. See each range, host count, and common use.
Fiber Connector Types
Reference guide to fiber optic connector types: LC, SC, ST, FC, MPO/MTP, and E2000 with polish, return loss, and typical use.
Ethernet Standards (IEEE 802.3)
Reference table of IEEE 802.3 Ethernet standards: 1000BASE-T, 10GBASE-T, 10GBASE-SR/LR, 25G, 40G, 100G, and 400G with media and distances.
RFC References for Network Engineers
Quick reference list of the essential networking RFCs every infrastructure engineer should know, from RFC 1918 to BGP, DHCP, DNS, and NTP.
Reserved & Special-Use IP Addresses
Reference table of special-use IPv4 ranges: loopback, link-local (APIPA), CGNAT, TEST-NET documentation ranges, multicast, and broadcast.
Cable Color Codes (TIA-606)
TIA-606 cable color codes for structured cabling: blue for horizontal cabling, orange for demarcation, purple for common equipment, and more.
Transceiver Form Factors
Reference table of optical transceiver form factors: SFP, SFP+, SFP28, QSFP+, QSFP28, QSFP-DD, CFP2, XFP, and CXP with speeds and distances.
WiFi Standards (IEEE 802.11)
Reference table of WiFi standards: 802.11b through 802.11be (Wi-Fi 1 to Wi-Fi 7) with maximum speeds, frequencies, and release years.
Power Connectors & Receptacles
Reference table of data center power connectors: NEMA 5-15P, L6-30P, IEC C13/C14, C19/C20, IEC 60309, Schuko, and BS 1363 with amp and voltage ratings.
Device Naming Conventions
Standard network device naming convention: use a <site>-<role>-<number> pattern. See examples for switches, firewalls, servers, and stack members.
Interface & Port Naming
How to standardize network interface names across vendors: Cisco IOS, Juniper Junos, and NX-OS/AOS-CX conventions with examples.
VLAN & Subnet Naming
Best practices for VLAN naming: descriptive names like SRV-PROD and GUEST-WIFI paired with documented VLAN IDs and subnets.