Administración de Red en Linux

Network details

/sbin/ifconfig -a
cat /etc/network/interfaces
cat /etc/sysconfig/network
ip a 
ip addr

cat /etc/resolv.conf
cat /etc/sysconfig/network
cat /etc/networks
iptables -L
hostname
dnsdomainname

Existing connections

lsof -i
lsof -i :80
grep 80 /etc/services
netstat -antup
netstat -antpx
netstat -tulpn
chkconfig --list
chkconfig --list | grep 3:on
last
w

## Cached IPs 
arp -e
route
/sbin/route -nee

### TCPDUMP
tcpdump tcp dst 192.168.1.7 80 and tcp dst 10.5.5.252 21

Networking

• Manage network interfaces

vi /etc/network/interfaces

• Set static ip

vi /etc/network/interfaces

# The primary network interface
auto eth0
iface eth0 inet static
address 10.0.0.100
netmask 255.255.255.0
gateway 10.0.0.1

Restart networking with $ service networking restart

• Networking:

  ping google.com
  # test two-way connectivity
  
  ping -c 4 google.com
  # sends 4 packets
  
  ifconfig
  # lists network interfaces configured
  
  ip a
  # modern alternative to ifconfig
  
  ip -s link
  # provides stats
  
  ip help
  # for more options
  
  ip route
  # view routing info
  
  route
  # similar info as 'ip route'
  
  nslookup google.com
  # dns lookup
  
  dig google.com
  # dns lookup with more info
  
  dig -x 8.8.8.8
  # reverse lookup
  
  netstat -at
  # view open TCP connections
  
  netstat -lt
  # listening TCP ports