Networking and System Administration

Step 1: Install/Enable your Wireless Card Step 2: Scan the media using 'iwlist scan' root@imran-laptop:~/Desktop# iwlist scan lo Interface doesn't support scanning. eth0 Interface doesn't support scanning. wlan0 Scan completed : Cell 01 - Address: 00:1B:11:5A:BC:48 Channel:1 Frequency:2.412 GHz (Channel 1) Quality=43/70 Signal level=-67 dBm Encryption key:on ESSID:"pingcom" Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s Bit Rates:6 Mb/s; 9 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s 36 Mb/s; 48 Mb/s; 54 Mb/s Mode:Master Extra:tsf=000008f601582180 Extra: Last beacon: 2732ms ago IE: Unknown: 000770696E67636F6D IE: Unknown: 010482848B96 IE: Unknown: 030101 IE: Unknown: 2A0100 I...

I am using I386 Machine with fresh install of ubuntu 8.04 Server and two interfaces. eth0----Internet eth2----use to listen dhcp request Step 1: Install the dhcp3-package First add following in /etc/apt/sources.list root@ubuntu:~# nano /etc/apt/sources.list deb http://security.ubuntu.com/ubuntu hardy-security main universe add and exit,then root@ubuntu:~# apt-get install dhcp3-relay Reading package lists... Done Building dependency tree Reading state information... Done The following NEW packages will be installed: dhcp3-relay 0 upgraded, 1 newly installed, 0 to remove and 7 not upgraded. Need to get 103kB of archives. After this operation, 274kB of additional disk space will be used. During Installation it will ask you, a) DHCP server IP address e.g your dhcp server address and b) Interface which you will listen for dhcp requests e.g eth2. Step 2: Enable forwarding. root@ubuntu:~# echo 1 > /proc/sys/net/ipv4/ip_forward root@ubuntu:~# echo 1 > /proc/sys/net/ipv4/tcp_synco...

Step 1: Fresh Install the Ubuntu server with option of DNS server during installation or you can install DNS latter in step 2. Step 2: Install DNS if not installed before root@ins# apt-get install bind9 Step 3: Edit /etc/bind/named.conf.options to disable recursion. By default the recursion is enables(yes), you can add /uncomment the follwoing line in option field. //recursion yes; //default recursion no; root@ins:/etc/bind# nano named.conf.options options { directory "/var/cache/bind"; // If there is a firewall between you and nameservers you want // to talk to, you might need to uncomment the query-source // directive below. Previous versions of BIND always asked // questions using port 53, but BIND 8.1 and later use an unprivileged // port by default. // query-source address * port 53; // If your ISP provided one or more IP addresses for stable // nameservers, you probably want to use them as forwarde...

Installation of useful tools. root@redmail:~# apt-get install acl wget dialog Copy following to /etc/apt/sources.list root@redmail:~# nano /etc/apt/sources.list deb http://ppa.launchpad.net/lidaobing/iredmail-804/ubuntu hardy main deb-src http://ppa.launchpad.net/lidaobing/iredmail-804/ubuntu hardy main Add key, you can replace your key, I used this "61270A939E324B12" and update. root@redmail:~#apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 61270A939E324B12 Executing: gpg --ignore-time-conflict --no-options --no-default-keyring --secret-keyring /etc/apt/secring.gpg --trustdb-name /etc/apt/trustdb.gpg --keyring /etc/apt/trusted.gpg --keyserver keyserver.ubuntu.com --recv-keys 61270A939E324B12 gpg: requesting key 9E324B12 from hkp server keyserver.ubuntu.com gpg: key 9E324B12: public key "Launchpad PPA for LI Daobing" imported gpg: Total number processed: 1 gpg: imported: 1 (RSA: 1) root@redmail:~# apt-get update Add mount option 'acl...

Here is your Ubuntu serve box with two interfaces, eth0-------------Internet eth2-------------Internal Note: Your Internet is running using eth0. Step1: Install DHCP Server #apt-get install dhcp3-server Step 2: Configure the DHCP server Edit the /etc/dhcp3/dhcpd.conf file and add your domain, dns, ip range and other options. option domain-name "oslohosting.com"; option domain-name-servers ns1.yourdns.com, xx.xx.xx.xx; # # Internal network # subnet 192.168.50.0 netmask 255.255.255.0 { range 192.168.50.100 192.168.50.200; option broadcast-address 192.168.50.255; option routers 192.168.50.1; default-lease-time 600; max-lease-time 7200; } Step 3: Configure the Internal interface (eth2) with static IP. Edit the /etc/network/interfaces file and add following iface eth2 inet static address 192.168.50.1 netmask 255.255.255.0 network 192.168.50.0 broadcast 192.168.50.255 gateway 192.168.50.1 Step 4: Restart network and verify the eth2 interface...