KfWiki: Getting vlan id

HomePage » Network

Cisco 3-layered network model

From http://www.mcmcse.com/cisco/guides/hierarchical_model.shtml

Cisco gears

SNMP config

Network Probe

Nmap

Software firewall

iptables
ipfw

Traffic shaping

Network Services

DNS
DHCP
Stunnel
OpenVPN

Other network stuff

ifconfig
Default gateway in different subnet
tcpdump
Arp caching

Getting vlan id

Need to see what vlan id an interface is connected to?

tcpdump -nn -v  -s 1500 -c 1 'ether[20:2] == 0x2000' -i eth0
# then do a broadcast ping, possibly on another screen

On Solaris:

snoop -d <interface> -x0 -v 'ether[20:2] = 0x2000'

Firewire networking

Firewire networking under linux is extremely easy. Tested on FC5
Note: On Fedora Core 7, firewall stack has been rewritten. Don't know what that means but the default kernel does not have eth1394 enabled. To use firewire networking, one need to re-compile the kernel.

modprobe eth1394
echo "alias eth1 eth1394 >> /etc/modprobe.conf"
ifconfig eth1 10.0.0.1 netmask 255.255.255.0

It's a little tricker to get firewire networking to work on FC6. I got the following after many attempts. Remember this will break when the kernel is upgraded.

alias eth1 eth1394
install eth1394 modprobe -k raw1394; insmod  /lib/modules/2.6.18-1.2798.fc6/kernel/drivers/ieee1394/eth1394.ko

tcpdump to capture arp converstaion

# tcpdump -ennqti eth0 \( arp or icmp \) | grep "00:16:d3:16:38:04"
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes
00:16:d3:16:38:04 > ff:ff:ff:ff:ff:ff, ARP, length 60: Request who-has 192.168.18.1 tell 192.168.18.150, length 46
00:16:d3:16:38:04 > ff:ff:ff:ff:ff:ff, ARP, length 60: Request who-has 192.168.18.50 tell 192.168.18.150, length 46
00:13:21:24:72:90 > 00:16:d3:16:38:04, ARP, length 60: Reply 192.168.18.50 is-at 00:13:21:24:72:90, length 46
00:16:d3:16:38:04 > ff:ff:ff:ff:ff:ff, ARP, length 60: Request who-has 192.168.18.13 tell 192.168.18.150, length 46
00:16:d3:16:38:04 > ff:ff:ff:ff:ff:ff, ARP, length 60: Request who-has 192.168.18.1 tell 192.168.18.150, length 46
00:16:d3:16:38:04 > ff:ff:ff:ff:ff:ff, ARP, length 60: Request who-has 192.168.18.1 tell 192.168.18.150, length 46

Network speed test with iperf

On one node, start the server process

iperf -s

On another node, start the client process. -t parameter specifies how many seconds the test should run.

iperf -c 1.2.3.4 -t 60

KfWiki : Network