User talk:TELE5330-F14-Group2

= The Folks = Yunwei Jiang mailto:jiang.yun@husky.neu.edu Tianhe Wang mailto:wang.tianh@husky.neu.edu Manish Reddy Bhimavarapu Samuelraj Vibin Mohanraj Samuel

= Motivation = = Understanding the Protocol = = The Requirements = = Steps to perform the setup / installation = = Testing = = Future Prospects = = Citations =

Linux Intruduction
Linux is an open source platform and a Unix-like and POSIX-complaint. Many developers working on Linux to develop applications, functions, features, etc to improve user experience. One of Linux's greatest feature is its low susceptibility to virus and malware infestation, which means that Linux is quite secure. The first Linux kernel was released by Linus Torvalds on Oct. 5 1991. Originally, Linux was developed as a free operating system for Intel x86-based PCs, as time flies by, it has since been used on different computer hardware platforms and it has been also developed as different versions like Red Hat, Ubuntu, CentOS. Linux can not only be used by computers, but it can also be implemented on embedded systems, showing its great compatibility and the embedded systems can include smart phones, network routers. Android, the most widely used operating system for tablets and smartphones, is built on top of the Linux kernel.

DHCP/Dynamic Host Configuration Protocol
DHCP

DHCP is the abbreviation of Dynamic Host Control Protocol which is a standard networking protocol and DHCP works with UDP. The two main uses of DHCP are: 1. To assign IP addresses for internal network or be used by ISPs to assign IP addresses dynamically; 2. A method to manage all computers centrally for uses or the administrators of internal network. And the two uses are well defined in RFC2131. Three Ports are used when implementing DHCP. The UDP ports 67 and 68 are used by DHCP servers and DHCP clients respectively for DHCP service. Port 546 is used by DHCPv6 clients but not DHCPv4 clients for DHCP failover service which is used for Hot-standby redundancy.

Behavior

The network model for DHCP is client-server model. The ISP assigns a range of IP addresses for the organization. And the organization will use a DHCP server to assign all these IP addresses to different hosts in the network dynamically so that every new coming host can get an IP address that won’t conflict with other hosts and thus it can get access to the Internet.

Signalling

DHCP service can be divided into 4 phases and they are 1) IP discovery 2) IP lease offer 3） IP request 4） IP lease acknowledgement IP discovery: Clients should be set to obtain IP addresses automatically and when a host want to get access to the Internet, it will send a broadcast query requesting for the DHCP server’s information so that it can communicate with the DHCP server directly. IP lease offer: DHCP server will receive an request from the client requesting for a IP lease and thus the server won’t recycle the IP address during the lease. IP request: The server will assigned an IP address to the client in response to the client’s request. IP lease acknowledgement: The server will send a acknowledgement confirming that the client has been given a lease for IP address.

Commands to configure IPv4

1） sudo apt-get install isc-dhcp-server

2） sudo vim /etc/default/isc-dhcp-server

Set the line "INTERFACE="eth0"

3） sudo vim /etc/dhcp/dhcpd.conf

The configuration are below

option domain-name "physicsboy.org";

option domain-name-servers 10.68.19.61;

option ip-forwarding on; default-lease-time 259200;

max-lease-time 518400; subnet 10.68.19.0 netmask 255.255.255.0 {

range 10.68.19.70 10.68.19.200;

option routers 10.68.19.62;

}

4） sudo service isc-dhcp-server restart

How to configure IPv6

1) sudo vim /etc/dhcp/dhcpd6.conf

The configurations are below:

default-lease-time 600;

max-lease-time 7200;

log-facility local7;

subnet6 2001:db8:0:1::/64{ range6 2001:db8:beef:53::10 2001:db8:beef:53::20; option dhcp6.nameservers 2001:db8:beef:53::3; options dhcp6.domain-search "physics.org"; } }
 * 1) Range for clients
 * 1) Additional options
 * 1) Prefix range for delegation to sub-routers
 * 2) prefix6 2001:db8:0:100:: 2001:db8:0:f00:: /56;
 * 3) Example for a fixed host address
 * 4) host unix{
 * 5) host-identifier option dhcp6.client-id 00"01:00:01:4a:1f:ba:e3:60:b9:19
 * 6) fixed-address6 2001:db8:beef:53:3:
 * }

2) sudo vim /etc/radvd.conf

3) sudo sysctl -w net.ipv6.conf.all.forwarding=1

4) service isc-dhcp-server restart

5) service isc-dhcp-server6 restart

6) service radvd restart

How to test

1) use the "tail /var/lib/dhcp/dhcpd.leases" to check the IP addresses and its lease;

2) ifconfig to see the IPv4 addresses and IPv6 address of the DHCP server.

"Flow Chat"

DNS/Domain Name System
DNS, or Domain Name System is a mapping distributed database of domain name and IP address and it helps users get access to the Internet easier without remembering IP addresses that can be recognized by the machines. The process of getting the IP addresses according to the host name is called domain name resolution. DNS runs over UDP and the port number is 53 and it is well defined in, ,.

Behavior

When the user types the domain name, the browser has to find the corresponding IP address. And a query is sent to local DNS server to find the matched IP address. The corresponding webpage will be sent back when the DNS server find it. However, if there is no records in local DNS server, the query will be delivered higher hierarchy DNS servers.

Signaling

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MaintenanceBot (discuss • contribs) 03:36, 2 December 2014 (UTC)