Common Network Ports Flashcards
What is the FTP port? (name, number and function)
File Transfer Protocol
tcp/20 (active mode data), tcp/21 (control)
– Transfers files between systems
* Authenticates with a username and password
– Some systems use a generic/anonymous login
* Full-featured functionality - List, add, delete, etc.
What is the SSH port? (name, number and function)
Secure Shell
Encrypted communication link - tcp/22
* Looks and acts the same as Telnet
What is the Telnet port? (name, number and function)
Telnet – Telecommunication Network - tcp/23
* Login to devices remotely
– Console access
* In-the-clear communication
– Not the best choice for production systems
What is the SNMP port? (name, number and function)
Simple Network Management Protocol
Gather statistics from network devices
– Queries: udp/161
– Traps: udp/162
- v1 – The original
– Structured tables
– In-the-clear - v2 – A good step ahead
– Data type enhancements
– Bulk transfers
– Still in-the-clear - v3 – A secure standard
– Message integrity
– Authentication
– Encryption
What is the SMTP port? (name, number and function)
- SMTP - Simple Mail Transfer Protocol
– Server to server email transfer - tcp/25 - Also used to send mail from a device to a mail server
– Commonly configured on mobile devices and email clients - Other protocols are used for clients to receive email
– IMAP, POP3
What is the DNS port? (name, number and function)
Domain Name System
- Converts names to IP addresses - udp/53
– www.professormesser.com = 162.159.246.164
* These are very critical resources
– Usually multiple DNS servers are in production
What is the DHCP port? (name, number and function)
Dynamic Host Configuration Protocol
Automated configuration of IP address, subnet mask and other options
- udp/67, udp/68
– Requires a DHCP server
– Server, appliance, integrated into a SOHO router, etc.
- Dynamic / pooled
– IP addresses are assigned in real-time from a pool
– Each system is given a lease and must renew at set intervals - DHCP reservation
– Addresses are assigned by MAC address in the DHCP server
– Manage addresses from one location
What is the HTTP and HTTPS port? (name, number and function)
Hypertext Transfer Protocol
tcp/80
Hypertext Transfer Protocol Secure
tcp/443
– Communication in the browser
– And by other applications
* In the clear or encrypted
– Supported by nearly all web servers and clients
What is the POP3 / IMAP port? (name, number and function)
- Receive emails from an email server
– Authenticate and transfer - POP3 - Post office Protocol version 3
– tcp/110
– Basic mail transfer functionality - IMAP4 - Internet Message Access Protocol v4
– tcp/143
– Includes email inbox management from multiple clients
What is the SMB port? (name, number and function)
Server Message Block
tcp/445
Protocol used by Microsoft Windows
– File sharing, printer sharing
– Also called CIFS (Common Internet File System)
What is the LDAP port? (name, number and function)
LDAP (Lightweight Directory Access Protocol) - tcp/389
- Store and retrieve information in a network directory
– Commonly used in Microsoft Active Directory
What is the RDP port? (name, number and function)
Remote Desktop Protocol
- Share a desktop from a remote location over tcp/3389
- Remote Desktop Services on many Windows versions
- Can connect to an entire desktop or just an application
- Clients for Windows, macOS, Linux, Unix, iPhone,
Android, and others
What is the NetBIOS over TCP/IP port? (name, number and function)
(Network Basic Input/Output System)
– udp/137 - NetBIOS name services (nbname)
– tcp/139 - NetBIOS session service (nbsession