- Servers maintain routing tables containing the addresses of each node in the network.
- The IP Routing protocols enable routers to build up a forwarding table that correlates final destinations with the next hop addresses.
- Displays currently active network interfaces.
- We may have to run as the superuser, or at least, give the full path, i.e., /sbin/ifconfig, on some distributions.
- Network Configuration Files are essential to ensure that interfaces function correctly.
- A very powerful and versatile program.
- Replaces most of the functionality of older
ifconfig,route,netstat, etc. - http://unix.stackexchange.com/questions/83096/what-is-the-difference-between-sbin-ip-route-and-sbin-route
- Sends a special network packet called an IMCP ECHO_REQUEST to a specified host.
- Check whether a machine attached to the network can receive and send data.
- Confirm that the remote host is online and is responding.
- Measure network latency between machines.
- Used to view or change the IP routing table.
- e.g., change the IP routing table to add, delete or modify specific (static) routes to specific hosts or networks
- Displays a listing of all the "hops" that network traffic takes to get from the local system to a specified host.
- Useful for troubleshooting network delays and errors.
- Allows us to isolate connectivity issues between hops, which helps resolve them faster
- Queries network interfaces and can also set various parameters such as the speed.
- Displays all active connections and routing tables.
- Useful for monitoring performance and troubleshooting.
- Scans open ports on a network. Important for security analysis
- Dumps network traffic for analysis.
- Monitors network traffic in text mode.
- Used to view a system’s hostname.
$ ip addr show
$ route –n
$ ip route show
$ route add -net address
$ route del -net address
- check if the remote host is alive and responding
ping <hostname>then abort byCtrl-Cping -c <n> <hostname>to specify the number of packets to be shown
$ ping mnishiguchi.com
PING mnishiguchi.com (192.30.252.153): 56 data bytes
64 bytes from 192.30.252.153: icmp_seq=0 ttl=54 time=15.744 ms
64 bytes from 192.30.252.153: icmp_seq=1 ttl=54 time=14.228 ms
^C
--- mnishiguchi.com ping statistics ---
13 packets transmitted, 12 packets received, 7.7% packet loss
round-trip min/avg/max/stddev = 14.228/18.630/24.027/3.395 ms
- For routers that do not provide identifying information (because of router configuration, network congestion, firewalls, etc.), we see
* * *.
$ traceroute mnishiguchi.com
traceroute to mnishiguchi.com (192.30.252.153), 64 hops max, 52 byte packets
1 10.0.0.1 (10.0.0.1) 14.108 ms 2.418 ms 2.962 ms
2 96.120.106.33 (96.120.106.33) 17.234 ms 15.315 ms 11.679 ms
3 xe-3-1-2-sur03.michiaganave.dc.bad.comcast.net (68.85.147.53) 12.732 ms 11.524 ms 21.986 ms
4 ae-5-0-ar01.capitolhghts.md.bad.comcast.net (68.86.204.205) 13.062 ms 45.409 ms 18.175 ms
5 ae13-ar01.capitolhghts.md.bad.comcast.net (68.87.168.61) 18.467 ms 21.439 ms 18.148 ms
6 be-33657-cr02.ashburn.va.ibone.comcast.net (68.86.90.57) 17.178 ms 16.239 ms 18.044 ms
7 be-10142-pe01.ashburn.va.ibone.comcast.net (68.86.86.34) 14.702 ms 12.925 ms 16.796 ms
8 66.208.229.158 (66.208.229.158) 14.368 ms 17.040 ms 13.704 ms
9 * * *
10 * * *
11 lb-192-30-252-153-iad.github.com (192.30.252.153) 17.718 ms 14.388 ms 12.612 ms
ethtool <devname>
e.g., showing information about the network device, eth0.
test1@ubuntu:~$ ethtool eth0
Settings for eth0:
Supported ports:[TP]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Supported pause frame use: No
Supports auto-negotiation: Yes
...
$ netstat -r
Routing tables
Internet:
Destination Gateway Flags Refs Use Netif Expire
default 10.0.0.1 UGSc 110 46 en0
...
Internet6:
Destination Gateway Flags Netif Expire
default fe80::200:caff:fe1 UGc en0
localhost localhost UHL lo0
...
$ hostname
Masas-Mac.local
wget http://mnishiguchi.com$ curl http://mnishiguchi.com -o outfile.html