Networking and System Administration

Installation of NFS on server Considering how powerful NFS is and the flexibility it gives you it is amazingly simple to set up. I expected it to be on a par with setting up Samba which can be a complete nightmare. Typically when setting up Samba one would use Swat or another configuration tool. With NFS set us is as easy as entering the paths you want exported into /etc/exports and making sure the correct packages are installed. There are two implementations of NFS one runs in kernel space (nfs-kernel-server) the other in user space (nfs-user-server). The kernel space implementation is faster and more stable but if something goes wrong it could bring your box down. In reality the kernel space NFS implementation very rarely fails. I have been running it for years (and on at least one occasion for 150 days straight) and have had it fail only a couple of times. The times it did fail it simply needed restarting. In fact the only way I have even managed to get it to make a noise is when...

Step 1:Install the subversion apt-get install subversion libapache2-svn Step 2: Create the repository svnadmin create /svn Configuration Edit the directory /etc/apache2/mods-enabled/dav_svn.conf # Uncomment this to enable the repository, DAV svn # Set this to the path to your repository SVNPath /svn # Uncomment the following 3 lines to enable Basic Authentication AuthType Basic AuthName “Subversion Repository” AuthUserFile /etc/apache2/dav_svn.passwd Require valid-user Save and exit the file Creation of user htpasswd -cm /etc/apache2/dav_svn.passwd imran New password: Re-type new password: Adding password for user imran Enable ssl (if required) #a2enmod ssl This will enable the ssl if you have problem to set it. Migration Export by :Dumping the existing repository root@jupiter:/svn# svnadmin dump svn > reposdump.dmp Import by: root@saturn:/srv# svnadmin load srv-jupiter

After installing the IPcop got the following error messages When running update the Error is: HTTP::Response=HASH(0x82a3c14)->code registered md5 When running download the Error is: HTTP::Response=HASH(0x82a3c68)->code The reason is that now snort.org publish rules now on current branch that are no more compatible with snort-2.6.1.5 We have manually add the current branch, to - date it is 2. You can find on snort if you have your account on snort.org under My Account-->My Oinkcodes along with the code (You must have account at snort to access code and use snort in IPCOP). Here is a solution, it is a manual fixation in the code. Open the /usr/local/bin/snortrules.pl in and editor. root@firewall:/etc/snort # nano /usr/local/bin/snortrules.pl Change the value to 2.8 at line no 55. my $rulesbranch= "2.8" ; # version should match snort branch version Save the change. Remember you must have to add the oink code in IPCOP--> Services-->INTRUSION DETECTION. Save-Appl...

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...

MEDIA AND TOPOLOGIES Peer-to-peer networks are useful for only relatively small networks. They are often used in small offices or home environments. Client/server networks, also called server-centric networks, have clients and servers. Servers pro video centralized administration, data storage, and security. The client system requests data from the server and displays the data to the end user. The bus network topology is also known as a linear bus because the computers in such a network are linked together using a single cable called a trunk, or backbone. If a terminator on a bus network is loose, data communications might be disrupted. Any other break in the cable will cause the entire network segment to fail. In a start configuration, all devices on the network connect to a central devices, and this central devices creates a single point of failure on the network. In the ring topology, the network layout forms a complete ring. comp...

1. What are 10Base2, 10Base5 and 10BaseT Ethernet LANs 10Base2—An Ethernet term meaning a maximum transfer rate of 10 Megabits per second that uses baseband signaling, with a contiguous cable segment length of 100 meters and a maximum of 2 segments. 10Base5—An Ethernet term meaning a maximum transfer rate of 10 Megabits per second that uses baseband google_protectAndRun("ads_core.google_render_ad", google_handleError, google_render_ad); signaling, with 5 continuous segments not exceeding 100meters per segment. 10BaseT—An Ethernet term meaning a maximum transfer rate of 10 Megabits per second that uses baseband signaling and twisted pair cabling. 2. Explain the difference between an unspecified passive open and a fully specified passive open An unspecified passive open has the server waiting for a connection request from a client. A fully specified passive open has the server waiting for a connection from a pecific client. 3. Explain the function of Transmission Control Block...

What is Testing? The process of exercising software to verify that it satisfies specified requirements and to detect errors. The process of analyzing a software item to detect the differences between existing and required conditions (that is, bugs), and to evaluate the features of the software item (Ref. IEEE Std 829). The process of operating a system or component under specified conditions, observing or recording the results, and making an evaluation of some aspect of the system or component. What is Test Automation? It is the same as Automated Testing. What is Acceptance Testing? Testing conducted to enable a user/customer to determine whether to accept a software product. Normally performed to validate the software meets a set of agreed acceptance criteria. What is Accessibility Testing? Verifying a product is accessible to the people having disabilities (deaf, blind, mentally disabled etc.). What is Ad Hoc Testing? A testing phase where the tester tries to 'break' the sys...