Difference between revisions of "Ethernet"

From Alessandro's Wiki
Line 56: Line 56:
  ip route show table main
  ip route show table main


*create 2 new tables, one for each uplink(1,2)
*create 2 new tables, one for each uplink2
echo 201 uplink1 >> /etc/iproute2/rt_tables
  echo 202 uplink2 >> /etc/iproute2/rt_tables
  echo 202 uplink2 >> /etc/iproute2/rt_tables


Line 63: Line 62:
  ip route add default via 1.2.3.1 table uplink2
  ip route add default via 1.2.3.1 table uplink2
  ip rule add from 1.2.3.4 table uplink2
  ip rule add from 1.2.3.4 table uplink2
ip route add 192.168.0.1/32 dev ens32 src 192.168.0.2 table uplink1
ip route add default via 192.168.0.1 table uplink1
ip rule add from 192.168.0.2 table uplink1

Revision as of 12:48, 11 June 2021

general Linux commands

ifconfig -a
  • attivare la scheda di rete eth0 (senza script di ifup/ifdown)
ifconfig eth0 up
  • disattivare la scheda di rete eth0 (senza script di ifup/ifdown)
ifconfig eth0 down
  • Chiedere in broadcast un indirizzo ip su eth0 (!!!)
dhclient eth0
  • Sapere se hai problemi con la scheda (il NIC)
# tail -50 /var/log/messages |grep -A4 eth0
NETDEV WATCHDOG: eth0: transmit timed out
Mar 26 14:21:39  kernel: eth0: transmit timed out, tx_status 00 status e000.
Mar 26 14:21:39 kernel:   diagnostics: net 0cf2 media 8880 dma 000000a0 fifo 0000
Mar 26 14:21:39 kernel:   Flags; bus-master 1, dirty 1048374(6) current 1048390(6)
Mar 26 14:21:39 kernel:   Transmit list 16c7f5c0 vs. d6c7f5c0.
  • scanneriz1zare una rete privata:
for a in `seq 1 254`; do echo -n -e "\r   $a   ";ping -c1 192.168.1.$a|grep "bytes from "; done

host scanning

  • nmap is the master tool, then everything follows.
nmap <host>
nmap -sS -p0-65535 -P0 -T4 --osscan_limit --osscan_guess --host_timeout 15m --max-retries 0 --min_parallelism 100 --max_parallelism 500 -O -oX -V <host>

subnet scan

  • this command will scan all host in the 10.10.10.0/24 subnet
nmap -sP 10.10.10.0-254
nmap -sP 192.168.82.0/24

Cisco

  • para conectar un host directo a un puerto de un router (Cisco)
cisco-6500#
cisco-6500#conf t
cisco-6500(config)#int gi3/44
cisco-6500(config-if)#spanning-tree port ?
 port-priority  portfast
cisco-6500(config-if)#spanning-tree portfast ?
 disable  Disable portfast for this interface
 trunk    Enable portfast on the interface even in trunk mode
 <cr>
cisco-6500(config-if)#spanning-tree portfast


== Linux Routing Table

  • example data
uplink1_ip=192.168.0.2
uplink1_gw=192.168.0.1
uplink1_if=ens31

uplink2_ip=1.2.3.4
uplink2_gw=1.2.3.1
uplink2_if=ens32
  • show main table (and save)
ip route show table main
  • create 2 new tables, one for each uplink2
echo 202 uplink2 >> /etc/iproute2/rt_tables
ip route add 1.2.3.1/32 dev ens32 src 1.2.3.4 table uplink2
ip route add default via 1.2.3.1 table uplink2
ip rule add from 1.2.3.4 table uplink2