| 20 |
FTP |
TCP |
File Transfer Protocol — data channel |
| 21 |
FTP |
TCP |
File Transfer Protocol — control channel |
| 22 |
SSH |
TCP |
Secure Shell — encrypted remote access |
| 23 |
Telnet |
TCP |
Unencrypted text communication (avoid in production) |
| 25 |
SMTP |
TCP |
Simple Mail Transfer Protocol — sending email |
| 53 |
DNS |
TCP/UDP |
Domain Name System — resolves hostnames to IPs |
| 67 |
DHCP |
UDP |
Dynamic Host Configuration Protocol — server |
| 68 |
DHCP |
UDP |
Dynamic Host Configuration Protocol — client |
| 80 |
HTTP |
TCP |
Hypertext Transfer Protocol — unencrypted web traffic |
| 110 |
POP3 |
TCP |
Post Office Protocol v3 — receiving email |
| 123 |
NTP |
UDP |
Network Time Protocol — clock synchronisation |
| 143 |
IMAP |
TCP |
Internet Message Access Protocol — receiving email |
| 194 |
IRC |
TCP |
Internet Relay Chat |
| 389 |
LDAP |
TCP |
Lightweight Directory Access Protocol |
| 443 |
HTTPS |
TCP |
HTTP Secure — encrypted web traffic |
| 445 |
SMB |
TCP |
Server Message Block — Windows file sharing |
| 465 |
SMTPS |
TCP |
SMTP over TLS — secure email sending |
| 514 |
Syslog |
UDP |
System Logging Protocol |
| 587 |
SMTP |
TCP |
SMTP mail submission (authenticated) |
| 636 |
LDAPS |
TCP |
LDAP over TLS |
| 993 |
IMAPS |
TCP |
IMAP over TLS |
| 995 |
POP3S |
TCP |
POP3 over TLS |
| 1194 |
OpenVPN |
UDP |
OpenVPN tunnelling |
| 1433 |
MSSQL |
TCP |
Microsoft SQL Server |
| 1521 |
Oracle DB |
TCP |
Oracle Database listener |
| 2049 |
NFS |
TCP |
Network File System |
| 3000 |
Dev server |
TCP |
Common Node.js / React / Rails development server |
| 3306 |
MySQL |
TCP |
MySQL / MariaDB database |
| 3389 |
RDP |
TCP |
Remote Desktop Protocol — Windows remote access |
| 4200 |
Angular |
TCP |
Angular CLI development server |
| 5000 |
Flask |
TCP |
Flask development server |
| 5432 |
PostgreSQL |
TCP |
PostgreSQL database |
| 5672 |
AMQP |
TCP |
RabbitMQ message broker |
| 5900 |
VNC |
TCP |
Virtual Network Computing — remote desktop |
| 6379 |
Redis |
TCP |
Redis in-memory data store |
| 6443 |
Kubernetes |
TCP |
Kubernetes API server |
| 8000 |
HTTP alt |
TCP |
Common alternative HTTP port |
| 8080 |
HTTP proxy |
TCP |
Common HTTP proxy / alternative web port |
| 8443 |
HTTPS alt |
TCP |
Common alternative HTTPS port |
| 8888 |
Jupyter |
TCP |
Jupyter Notebook server |
| 9200 |
Elasticsearch |
TCP |
Elasticsearch REST API |
| 9300 |
Elasticsearch |
TCP |
Elasticsearch inter-node communication |
| 15672 |
RabbitMQ |
TCP |
RabbitMQ management web console |
| 27017 |
MongoDB |
TCP |
MongoDB database |
| 50070 |
Hadoop |
TCP |
Hadoop HDFS NameNode web UI |