| 20 |
TCP |
FTP (File Transfer Protocol) – Data Transfer |
Allow for file transfers |
| 21 |
TCP |
FTP (File Transfer Protocol) – Command Control |
Allow for FTP server access |
| 22 |
TCP |
SSH (Secure Shell) |
Secure remote administration |
| 23 |
TCP |
Telnet (Unsecured Remote Login) |
Not recommended; disable unless required |
| 25 |
TCP |
SMTP (Simple Mail Transfer Protocol) |
Allow for mail servers |
| 53 |
TCP/UDP |
DNS (Domain Name System) |
Required for name resolution |
| 67 |
UDP |
DHCP (Dynamic Host Configuration Protocol) – Server |
Allow for DHCP server |
| 68 |
UDP |
DHCP (Dynamic Host Configuration Protocol) – Client |
Required for dynamic IP allocation |
| 69 |
UDP |
TFTP (Trivial File Transfer Protocol) |
Used in PXE boot and network devices |
| 80 |
TCP |
HTTP (Hypertext Transfer Protocol) |
Web traffic (open for web servers) |
| 88 |
TCP/UDP |
Kerberos (Authentication Protocol) |
Required for Active Directory authentication |
| 110 |
TCP |
POP3 (Post Office Protocol v3) |
Mail client retrieval (legacy) |
| 119 |
TCP |
NNTP (Network News Transfer Protocol) |
News services (rarely used) |
| 123 |
UDP |
NTP (Network Time Protocol) |
Allow for time synchronization |
| 135 |
TCP/UDP |
RPC (Remote Procedure Call) |
Used by Windows services (firewall exception needed) |
| 137-139 |
TCP/UDP |
NetBIOS (Windows File Sharing) |
Legacy Windows sharing (disable for security) |
| 143 |
TCP |
IMAP (Internet Message Access Protocol) |
Modern email retrieval |
| 161-162 |
UDP |
SNMP (Simple Network Management Protocol) |
Used for network monitoring |
| 389 |
TCP/UDP |
LDAP (Lightweight Directory Access Protocol) |
Used for Active Directory queries |
| 443 |
TCP |
HTTPS (Secure HTTP) |
Secure web traffic |
| 445 |
TCP |
SMB (Server Message Block – File Sharing) |
Windows file sharing (should be secured) |
| 465 |
TCP |
SMTPS (Secure SMTP) |
Encrypted email sending |
| 500 |
UDP |
IPSec (Internet Key Exchange) |
VPN and secure communications |
| 514 |
UDP |
Syslog (System Logging Protocol) |
Network device logging |
| 587 |
TCP |
SMTP (Email Submission) |
Secure email transmission |
| 636 |
TCP |
LDAPS (Secure LDAP) |
Secure Active Directory queries |
| 989-990 |
TCP |
FTPS (Secure FTP) |
Encrypted file transfers |
| 993 |
TCP |
IMAPS (Secure IMAP) |
Secure email retrieval |
| 995 |
TCP |
POP3S (Secure POP3) |
Encrypted mail retrieval |
| 1433 |
TCP |
Microsoft SQL Server |
Database access (firewall must allow) |
| 1521 |
TCP |
Oracle Database |
Oracle database connections |
| 1723 |
TCP |
PPTP (Point-to-Point Tunneling Protocol) |
VPN connectivity |
| 1812-1813 |
UDP |
RADIUS (Authentication and Accounting) |
Network authentication service |
| 3306 |
TCP |
MySQL Database |
Open for MySQL database access |
| 3389 |
TCP |
RDP (Remote Desktop Protocol) |
Allow for remote desktop access (secure via firewall) |
| 5060-5061 |
TCP/UDP |
SIP (VoIP Communication) |
VoIP service ports |
| 5432 |
TCP |
PostgreSQL Database |
Open for PostgreSQL connections |
| 5900 |
TCP |
VNC (Virtual Network Computing – Remote Access) |
Allow if remote access is needed |
| 8080 |
TCP |
HTTP Alternative (Common Proxy Port) |
Used for alternative web services |
| 8443 |
TCP |
HTTPS Alternative |
Secure alternative for web services |
| 5985 |
TCP |
WinRM (Windows Remote Management – HTTP) |
Used for remote management (should be secured) |
| 5986 |
TCP |
WinRM (Windows Remote Management – HTTPS) |
Secure remote PowerShell management |
| 8500-8502 |
TCP |
Windows Server Clustering |
Used for Windows Failover Clustering |
| 1434 |
UDP |
SQL Server Browser |
Helps clients find SQL instances |
| 5355 |
UDP |
LLMNR (Link-Local Multicast Name Resolution) |
Used in name resolution (disable for security) |
| 49152-65535 |
TCP/UDP |
Dynamic Ports (Ephemeral Ports) |
Used by various Windows services |
