Archive for category Networking
File Transfer protocol
To access ftp using command line from windows
What is DHCP?
Dynamic Host Configuration Protocol (DHCP) is a network protocol that enables a server to automatically assign an IP address to a computer from a defined range of numbers (i.e., a scope) configured for a given network.
DHCP assigns an IP address when a system is started, for example:
- A user turns on a computer with a DHCP client.
- The client computer sends a broadcast request (called a DISCOVER or DHCPDISCOVER), looking for a DHCP server to answer.
- The router directs the DISCOVER packet to the correct DHCP server.
- The server receives the DISCOVER packet. Based on availability and usage policies set on the server, the server determines an appropriate address (if any) to give to the client. The server then temporarily reserves that address for the client and sends back to the client an OFFER (or DHCPOFFER) packet, with that address information. The server also configures the client’s DNS servers, WINS servers, NTP servers, and sometimes other services as well.
- The client sends a REQUEST (or DHCPREQUEST) packet, letting the server know that it intends to use the address.
- The server sends an ACK (or DHCPACK) packet, confirming that the client has a been given a lease on the address for a server-specified period of time.
When a computer uses a static IP address, it means that the computer is manually configured to use a specific IP address. One problem with static assignment, which can result from user error or inattention to detail, occurs when two computers are configured with the same IP address. This creates a conflict that results in loss of service. Using DHCP to dynamically assign IP addresses minimizes these conflicts.
These are the port that we are commonly using
Port numbers range from 0 to 65536, but only ports numbers 0 to 1024 are reserved for privileged services and designated as well-known ports. This list of well-known port numbers specifies the port used by the server process as its contact port.
|1||TCP Port Service Multiplexer (TCPMUX)|
|5||Remote Job Entry (RJE)|
|18||Message Send Protocol (MSP)|
|20||FTP — Data|
|21||FTP — Control|
|22||SSH Remote Login Protocol|
|25||Simple Mail Transfer Protocol (SMTP)|
|42||Host Name Server (Nameserv)|
|49||Login Host Protocol (Login)|
|53||Domain Name System (DNS)|
|69||Trivial File Transfer Protocol (TFTP)|
|108||SNA Gateway Access Server|
|115||Simple File Transfer Protocol (SFTP)|
|137||NetBIOS Name Service|
|139||NetBIOS Datagram Service|
|143||Interim Mail Access Protocol (IMAP)|
|150||NetBIOS Session Service|
|179||Border Gateway Protocol (BGP)|
|190||Gateway Access Control Protocol (GACP)|
|194||Internet Relay Chat (IRC)|
|197||Directory Location Service (DLS)|
|389||Lightweight Directory Access Protocol (LDAP)|
|396||Novell Netware over IP|
|444||Simple Network Paging Protocol (SNPP)|
Port in computer refers to the connection point whether it may be physical or virtual
These are the port which is connected physical like cable,modem,routers,etc.,