Professor Messer - Professor Messers's CompTIA A+ 220-1001 2.1 network ports.pdf

2.1 - Common Network Ports FTP – 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. SSH - Secure Shel...

2.1 - Common Network Ports FTP – 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. SSH - Secure Shell • Encrypted communication link - tcp/22 • Looks and acts the same as Telnet Telnet • Telnet – Telecommunication Network - tcp/23 • Login to devices remotely • Console access • In-the-clear communication • Not the best choice for production systems 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 DNS - 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 HTTP and HTTPS • Hypertext Transfer Protocol - tcp/80 • Communication in the browser • And by other applications • In the clear or encrypted - HTTPS - tcp/443 • Supported by nearly all web servers and clients POP / IMAP • 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 management of email inbox from multiple clients RDP - 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 SMB - Server Message Block • Protocol used by Microsoft Windows • File sharing, printer sharing • Also called CIFS (Common Internet File System) • Using NetBIOS over TCP/IP • udp/137 - NetBIOS name services (nbname) • udp/138 - NetBIOS datagram service (nbdatagram) • tcp/139 - NetBIOS session service (nbsession) • Direct over tcp/445 (NetBIOS-less) • Direct SMB communication over TCP without the NetBIOS transport AFP (Apple Filing Protocol) • File services in macOS • tcp/548 • Works with SLP (Service Location Protocol) • tcp/427 and udp/427 • Populates the list of available devices • File management • Copy, move, delete files DHCP - 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 • Quickly manage addresses from one location LDAP (Lightweight Directory Access Protocol) • tcp/389 • Store and retrieve information in a network directory • Commonly used in Microsoft Active Directory SNMP - 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 2.1 - Common Network Ports (continued) Protocol Port Name Descrip/on FTP tcp/20, tcp21 File Transfer Protocol Sends and receives files between systems SSH tcp/22 Secure Shell Encrypted console access Telnet tcp/23 TelecommunicaCon Network Insecure console access SMTP tcp/25 Simple Mail Transfer Protocol Transfer email between mail servers DNS udp/53, tcp/53 Domain Name System Convert domain names to IP addresses HTTP HTTPS tcp/80 tcp/443 Hypertext Transfer Protocol Hypertext Transfer Protocol Secure Web server communicaCon Web server communicaCon with encrypCon POP3 IMAP4 tcp/110 tcp/143 Post Office Protocol version 3 Internet Message Access Protocol v4 Receive email into a email client A newer email client protocol RDP NetBIOS tcp/3389 udp/137 Remote Desktop Protocol NetBIOS name service Graphical display of remote devices Register, remove, and find Windows services by name NetBIOS udp/138 NetBIOS datagram service Windows connecConless data transfer NetBIOS tcp/139 NetBIOS session service Windows connecCon-oriented data transfer SMB tcp/445 Server Message Block Windows file transfers and printer sharing AFP tcp/548 Apple Filing Protocol Mac OS file transfers SLP tcp/427, udp/427 Service LocaCon Protocol Find Mac OS services by name DHCP udp/67, udp/68 Dynamic Host ConfiguraCon Protocol Automate the IP address configuraCon process LDAP tcp/389 Lightweight Directory Access Protocol Directory services SNMP udp/161 Simple Network Management Protocol Gather metrics and manage network devices