Common Ports and the OSI Model Flashcards

1
Q

Telnet

A
  1. TCP/23 port
  2. Login to rdevices remotely.
  3. console access
  4. in the clear no secure Auth
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2
Q

SSH -

A

Secure Shell

  1. TCp/22 port
  2. Encrypted
  3. Replacement for Telnet
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3
Q

DNS

A

Domain Naming System

  1. UDP/53
  2. Resolves hostnames to IP address.
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4
Q

SMTP

A

Simple Mail Transfer Protocol

  1. TCP/25
  2. Sends mail from one server to another.
  3. Sends mail from mobile device and email clients.
  4. Not used for receiving email (IMAP/POP3)
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5
Q

SFTP

A

Secure File transfer Protocol

  1. TCP/22
  2. Uses SSH to transfer files.
  3. Resuming interrupted transfers, directy listings, file removal.
  4. Encrypted information.
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6
Q

FTP

A

File Transfer Protocol

  1. TCP/20 (active mode data)
  2. TCP/21 (control)
  3. Authenticates with a username and password.

Full-featured functionality (list add delete etc)

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7
Q

TFTP -

A

Transfer File Protocol

  1. UDP/69
  2. Very simple FT app
  3. No authentication.
  4. Not used on production systems
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8
Q

DHCP -

A

Dynamic Host Configuration Protocol

  1. UDP/67 and 68.
  2. Requires a DHCP server (server, appliance, integrated into a small office home office router, etc)
  3. Dynamic/pooled ip address are assigned in real time from a pool.
  4. Each system is given a lease and must renew at set intervals.
  5. DHCP reservation (addresses are assigned by MAC address in the DHCP server)
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9
Q

HTTP and HTTPS

A

Hypertext Transfer Protocol

  1. TCP/80 (HTTP
  2. TCP/443 (HTTPS)
  3. Communication in the browser and by other apps.
  4. In the clear or encrypted.
    - Supported by nearly all web servers and clients.
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10
Q

SNMP -

A

Simple Network Management Protocol

  1. UDP/161
    - Gathers statistics from network devices.
  2. v1 - The original
    - Structured tables
    - in-the-clear
  3. v2 - a good step ahead
    - Data type enhancements
    - Bulk transfers
    - Still in-the-clear
  4. v3 - A secure standard
    - Message integrity
    - Authentication
    - Encryption.
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11
Q

RDP -

A

Remote Desktop Protocol

  1. TCP/3389
  2. Share a desktop from a remote location.
  3. Remote Desktop Services on many Windows versions
  4. Can connect to an entire desktop or just an app.
  5. Clients for Windows, MACOs, Linux, Unix, iPhone and others.
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12
Q

NTP

A

Network Time Protocol

  1. UDP/123
  2. Switches, routers, firewalls, servers, workstations
    - Every device has it’s own clock
  3. Synchronizing clocks becomes critical
    - Log files, auth information, outage details
  4. Automatic updates
    - No flashing 12:00 lights
  5. Very accurate
    - Accuracy better than 1ms
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13
Q

SIP

A

Session Initiation Protocol

  1. TCP/5061-5061
  2. Setup and manage VoIP sessions
    - Call, ring, hangup
  3. Extend voice comms
    - Video conferencing
    - Instant messaging
    - File transfer
    - etc
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14
Q

SMB

A

Server Message Block

  1. TCP/445 (NetBIOS-less)
  2. Protocol used by Microsoft Windows
    - File sharing, print sharing
    - Allso called CIFS (Common Internet File System)
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15
Q

POP/IMAP

A
  1. Receives emails from an email server

POP3 - Post office Protocol v3

  • TCP/110
  • Basic mail transfer functionality

IMAP4 - Internet Message Access Protocol v4

  • TCP/143
  • Includes management of email inbox from multiple clients
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16
Q

LDAP - Lightweight Directory Access Protocol

A

Lightweight Directory Access Protocol

  • TCP/389
  • Store and retrieve information in a network directory

Lightweight Directory Access Protocol Secure

  • TCP/636
  • Non-standard implementation of LDAP over SSL
17
Q

H.323

A
  1. Voice over IP (VoIP) signlaing
    - TCP/1720
    - ITU Telecommunication H.32x protocol series
  2. Setup and manage VoIP sessions
    - Call, ring, hangup
  3. One of the earliest VoIP standards
    - Still in use today
18
Q

OSI Model

A

Open Systems Interconnection Reference Model

  • It’s a guide
  • Don’t get wrapped up in the details
  • All People Seem To Need Data Processing
19
Q

Layer 1

A

Physical Layer

  • Signaling, cabling, connectors
  • This layer isn’t about protocols

You have a physical layer problem

  • Fix your calbing, punch-downs, etc
  • Run loopback tests, test/replace cables, swap adapter cards
20
Q

Layer 2

A

Data Link Layer

The basic network language
- Foundation of communication at the data link layer

Data Link Control (DLC) protocols
-MAC (Media Access Control) address on ethernet

The Switching layer

21
Q

Layer 3

A

Network or routing layer

Internet Protocol (IP)

Fragments frames to traverse different networks

22
Q

Layer 4

A

Transport Layer

Post office layer
- Parcels and letters

TCP (Transmission Control Protocol) and UDP (User Datagram Protocol)

When you hear layer 4 or layer 4 protocol almost always refers to TCP or UDP.

23
Q

Layer 5

A

Session Layer

Communication management between devices
- Start, stop, restart

Control protocols, tunneling protocols
- “Can we talk” “yes we can”

24
Q

Layer 6

A

Presentation Layer

Character encoding
-Application encryption (SSL/TLS)

Often combined with application layer

25
Q

Layer 7

A

Application Layer

Responsible for what we see