Koerner.De: RH_Networking

Config files

Documentation: /usr/share/doc/initscripts-*/sysconfig.txt

/etc/sysconfig/network-scripts	contains the data for each interface
/etc/sysconfig/network	can contain fqdn Hostname and defaultroute
/etc/resolv.conf	warning ca be rewritten by dhcp if the interface has not `PEERDNS=no`
/etc/hosts

Net Configuration

The preferred command to handle Interface config is /sbin/ip.

ip addr show	shows complete interfaceconfig
ip route	routing
ip -6 route	IPv6 Routing

/etc/sysconfig/network-scripts

Static	DHCP	Any
BOOTPROTO=static	BOOTPROTO=dhcp	DEVICE=eth0
IPADDR=a.b.c.d		ONBOOT=yes
PREFIX=24		HWADDR=53:54:00:00:00:FA
GATEWAY=a.b.c.d		NM_CONTROLLED=yes
DNS1=a.b.c.d

to activate changes use ifup and ifdown

ethtool -p eth0 30

blink network card

services

disable NetworkManager, because he doesn't work with bonding and aliases
service NetworkManager stop ; chkconfig NetworkManager off

Restart Network stuff service network restart

Bonding

Documentation can be found in /usr/share/doc/kernel-*/Documentation/networking/bonding.txt

Definition

master	The "virtual" Bonding interface carrying the configuration
slave	The "physical" Interfaces used by the master

Bonding modes

Mode 0	balance-rr
Mode 1	active-backup
Mode 3	broadcast

Define Bonding Interface in /etc/modprobe.d/bonding.conf.

alias bond0 bonding

Define the slave interfaces /etc/sysconfig/network-scripts/ifcfg-<dev>

DEVICE=<dev>
BOOTPROTO=none
ONBOOT=yes
MASTER=<bondx>
SLAVE=YES
USERCTL=no

Define the master interface /etc/sysconfig/network-scripts/ifcfg-<bondX>

DEVICE=bond0
...
BONDING_OPTS="mode=1 miimon=50"

Kernel config

Install Kernel Docs: yum -y install kernel-doc
Documentation can be found in /usr/share/doc/kernel-*/Documentation/sysctl/ip-sysctl.txt

net.ipv4.icmp_echo_ignore_all = X
net.ipv4.icmp_echo_ignore_broadcasts = X

Config File for sysctl stuff: /etc/sysctl.conf

Debugging

Finding Switchport via CDP

tcpdump -nn -v -i eth0 -s 1500 -c 1 'ether[20:2] == 0x2000'

RH Networking