This article describes how to enable promiscuous mode on a physical Network Interface Card (NIC). In a network, promiscuous mode allows a network device to intercept and read each network packet that arrives in its entirety. This mode of operation is sometimes given to a network snoop server that captures and saves all packets for analysis (for example, when monitoring network usage).

Instructions

Enable Promiscuous Mode

1. To enable the promiscuous mode on the physical NIC, run the following command on the XenServer text console:
   # ifconfig eth0 promisc

2. Run the ifconfig command and notice the outcome:
   eth0   Link encap:Ethernet  HWaddr 00:1D:09:08:94:8A
             inet6 addr: fe80::21d:9ff:fe08:948a/64 Scope:Link
             UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
             RX packets:23724 errors:0 dropped:0 overruns:0 frame:0
             TX packets:7517 errors:0 dropped:0 overruns:0 carrier:0
             collisions:0 txqueuelen:1000
             RX bytes:2169478 (2.0 MiB)  TX bytes:5423377 (5.1 MiB)
             Interrupt:17

Disable Promiscuous Mode

1. To disable promiscuous mode on the physical NIC, run the following command on the XenServer text console:
   # ifconfig eth0 –promisc

2. Run the ifconfig command again and notice that promiscuous mode is now disabled.