2.0 Networking

What ports does FTP use?

Port 20 = Active Mode (data), Port 21 = Control channel (commands).

What is FTP used for?

Transfer files between system.

Which protocol does FTP use?

TCP.

What is SSH used for?

Secure remote login, encrypted replacement for Telnet.

What is the port and protocol for SSH?

Port 22, TCP.

Key points for Telnet?

Remote login, unencrypted, legacy/insecure, TCP port 23.

Port and protocol for SMTP?

TCP port 25.

SMTP Function?

Sends email between mail servers, outbound client email.

DNS Port numbers?

UDP 53 for queries, TCP 53 for zone transfers/large queries.

DNS Function?

Translate domain names to IP addresses.

DHCP Ports?

Server = 67, Client = 68 (UDP).

DHCP purpose?

Automatically assigns IP, subnet mask, gateway, DNS.

HTTP port and protocol?

TCP port 80, unencrypted web traffic.

HTTPS port and protocol?

TCP port 443, encrypted web traffic (TLS/SSL).

POP3?

Port 110, TCP; downloads email to local client, usually removes from server.

IMAP?

Port 143, TCP; email sync, keeps messages on server, modern preferred protocol.

NetBIOS ports and functions?

137 = Name Service, 138 = Datagram, 139 = Session; TCP/UDP

SMB / CIFS?

Windows file and printer sharing, modern NETBIOS functions, TCP port 445.

LDAP port and protocol?

TCP/UDP port 389 (mostly TCP).

LDAP function?

Directory services (Active Directory), read/write directory objects.

RDP port and protocol?

TCP port 3389 (sometimes UDP enhancements).

RDP functions?

Full remote GUI access.

TCP characteristics?

Connection-oriented, reliable, error checking, slower. Used for web, email, file transfer.U

UDP characteristics?

Connectionless, fast, unreliable, no retransmission. Used for streaming, VoIP, gaming.

Key characteristics of 2.4 GHz Wi-Fi?

Longer range, lower speed, penetrates walls, more interference (Bluetooth, microwaves), used by 802.11b/g/n (optional).Ke

Key characteristics of 5 GHz Wi-Fi?

Shorter range, higher speeds, less interference, poor wall penetration, used by 802.11a/ac.

Key characteristics of 6 GHz Wi-Fi (Wi-Fi6)?

Shortest range, highest speeds, requires newer devices, very low congestion, used by 802.11ax.

How are channels regulated in the U.S.?

Managed by the FCC; determines allowed channels, power levels, DFS requirements, intended usage.

Recommended channel widths?

• 20 MHz = most stable, required for 2.4 GHz

• 40 MHz = faster, may overlap 2.4 GHz

• 80 MHz = common in 5 GHz

• 160 MHz = highest speed, needs clean spectrum

Non-overlapping 2.4 GHz channels?

1, 6, 11.

5 GHz channel details?

Many non-overlapping channels; some require DFS to avoid radar.

6 GHz channel details?

Very wide bandwidth, mostly non-DFS, minimal interference.

Bluetooth frequency and range?

Operates at 2.4 GHz; Class 2 ~ 10m, Class 1 up to 100m

Common uses of Bluetooth?

Mice, keyboards, headsets, file transfers, tethering, IoT devices.

Bluetooth verions?

• 4.x = Low Energy (BLE)

• 5.x = Greater range, higher speed, improved IoT support

802.11a?

5 GHz, 54 Mbps, less interference.

802.11b?

2.4 GHz, 11 Mbps, long range, high interference.

802.11g?

2.4 GHz, 54 Mbps, backwards compatible with 802.11b.

802.11n (Wi-Fi 4)?

2.4 and 5 GHz, ~600 Mbps, MIMI, dual-band.

802.11ac (Wi-Fi 5)?

5 GHz, ~9.6 Gbps, MU-MIMO, 80-160 MHz channels.

802.11ax (Wi-Fi 6/6E)?

2.4, 5, 6 GHz, ~9.6 Gbps, OFDMA, high-density optimization.

NFC range and frequency?

Very short (~4 cm), operates at 13.56 MHz.

Common uses of NFC?

Tap-to-pay, phone-to-phone sharing, paring Bluetooth devices, access cards.K

Key NFC characteristics?

Very low power, extremely short range, often used to establish secure connections.

What is RFID used for?

Identify, track, authenticate objects (inventory, key fobs, tolls, passports, assets).

Types of RFID?

• Passive = no battery, powered by reader, short range.

• Active = has battery, long range (hundreds of meters).

RFID frequency ranges?

Low, high, UHF depending on tag type.

What does DNS do?

Translates domain names into IP addresses, essential for web browsing and network operations.