Network Monitoring tools in Linux

Network monitoring tools are used to monitor the network, systems present on the network, various service running on the network, traffic etc.

Ping: Ping command is used to check if the system is in the network or not. To check if the host is operating.

e.g. ping ip_address

[root@server1 ~]# ping 172.26.128.132

PING 172.26.128.132 (172.26.128.132) 56(84) bytes of data.

64 bytes from 172.26.128.132: icmp_seq=0 ttl=58 time=3.27 ms

64 bytes from 172.26.128.132: icmp_seq=1 ttl=58 time=3.12 ms

64 bytes from 172.26.128.132: icmp_seq=2 ttl=58 time=1.92 ms

64 bytes from 172.26.128.132: icmp_seq=3 ttl=58 time=3.10 ms

64 bytes from 172.26.128.132: icmp_seq=4 ttl=58 time=2.14 ms

--- 172.26.128.132 ping statistics ---

5 packets transmitted, 5 received, 0% packet loss, time 4006ms

rtt min/avg/max/mdev = 1.922/2.715/3.279/0.564 ms, pipe 2

[root@server1 ~]#

When the command is executed, it returns a detailed summary of the host. Packets sent, received, lost by estimating the round trip time.

Traceroute: the command is used to trace the path taken by the packet across a network. Tracing the path here means finding out the hosts visited by the packet to reach its destination. This information is useful in debugging. Roundtrip time in ms is shown for every visit to a host.

Tcpdump: commonly used to monitor network traffic. Tcdump captures and displays packet headers and matching them against criteria or all. It interprets Boolean operators and accepts host names, ip address, network names as arguments.

Ntop: Network top shows the network usage. It displays summary of network usage by machines on the network in a format as of UNIX top utility. It can also be run in web mode, which allows the display to be browsed with a web browser. It can display network traffic statistics, identify host etc. Interfaces are available to view such information.

Comments

Virtual Box and Alt/Tab Keys

I use virtual box for all my testing activities. It comes too often that I have a virtual box VM window open & I want to switch to my host machine to see some stuff like tutorials etc.. If you press the alt+tab combination it just works inside the VM & doesn't switches to host machine. In these scenarios you can press the host key once ( not hold it ) & then whatever you press goes to host machine. So in general where host key is the default Right Ctrl, just press Right Ctrl once & now press the alt+tab & it will switch you out to host machine. This is really helpful when you have the VM windows open or you're working on seamless mode. Hope it help others too.

CentOS / Redhat : Configure CentOS as a Software Router with two interfaces

Linux can be easily configured to share an internet connection using iptables. All you need to have is, two network interface cards as follows: a) Your internal (LAN) network connected via eth0 with static ip address 192.168.0.1 b) Your external WAN) network is connected via eth1 with static ip address 10.10.10.1 ( public IP provided by ISP ) Please note that interface eth1 may have public IP address or IP assigned by ISP. eth1 may be connected to a dedicated DSL / ADSL / WAN / Cable router: Step # 1: Enable Packet Forwarding Login as the root user. Open /etc/sysctl.conf file # vi /etc/sysctl.conf Add the following line to enable packet forwarding for IPv4: net.ipv4.conf.default.forwarding=1 Save and close the file. Restart networking: # service network restart Step # 2: Enable IP masquerading In Linux networking, Network Address Translation (NAT) or Network Masquerading (IP Masquerading) is a technique of transce...

AMD Radeon™ HD 7670M on Ubuntu 12.04

Update: Recently I install kubuntu 13.10 and there is no problem with graphics. It just works fine out of the box. I've seen many blog posts on how to make AMD HD7670M work on Ubuntu 12.04, specially when its in switchable graphics board like Dell Inspiron 15R 5520. I tried many things to make it work so that I could use the cinnamon desktop on ubuntu & other things too.. But to my surprise even the drivers from AMD site didn't work. Then I tried a combination of those blog posts I read & somehow I became successful in running the full graphics including compiz settings inside My Ubuntu Machine. Following are the steps I followed & it worked... 1. Create a backup of your xorg configuration file: sudo cp /etc/X11/xorg.conf /etc/X11/xorg.conf.BAK 2. Remove/purge current fglrx and fglrx-amdcccle : sudo apt-get remove --purge fglrx* 3. Install the driver: sudo apt-get install fglrx fglrx-amdcccle 4. Install additiona...

Linux Tech Tips

Search This Blog