January 5, 2016 sysadmin networking

'(CentOS 7 Networking Tools)

  1. Packages
  2. Commands
  3. Files
  4. Normal Things
  5. Antiquated/Deprecated
  6. Glossary
  7. Resources

Audience: sysadmins

“Networking is an essential part of building wealth.” — Armstrong Williams

The networking toolchain is a bit different on every OS. I’ve been spending enough time on CentOS 7 lately that its specifics are worth recording.

I’ll assume you don’t care about OSs that deviate much from RH-derived. I’m also leaving out anything to do with IPv6.

Wireless networking is not something you do much on servers, so it (iw) is mostly omitted, too.

Packages

iproute2

Commands

The ip command has replaced some of the trusty old guard. If you use Zsh, the ip tab-completion is excellent for quickly using various subcommands.

wolfram cidr
ethtool
ip a
ip link
ifconfig
ifstat
ifup/ifdown
nmcli/nmtui
nmcli d s
NetworkManager (need it for firewalld)
sys
netstat -tulpn
netstat -pn tcp
netstat -ln4
netstat -naf inet
ss (socket stat)
netcat
arp
route
iotop
iostat
iperf3
host
whois/dig
ping
lsof -ni
tcpdump
ipcalc
ifrename
sockstack -4

Although traceroute is the old standard, the netadmins I’ve worked with tend to ask for mtr output.

mtr/tracepath
firewall-cmd
iostat -xdm 5

Files

/etc/sysconfig/network-scripts/ifcfg-e*
/etc/services
/etc/resolv.conf

Normal Things

pinging local Gb network: 0.15 ms

Antiquated/Deprecated

arp
iptunnel
iwconfig
nameif
netstat
route
ifconfig
traceroute
tcpdump

yum install net-tools (last release 2001 https://lists.debian.org/debian-devel/2009/03/msg00780.html)

Glossary

uplink

incoming network drop

layers (physical, datalink, network, transport, app)
tcp/ip
nat
private addresses

10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16 https://en.wikipedia.org/wiki/Private_network

arp/mac address
cidr
lan
vlan (multi-homing)
netmask
broadcast
gateway
icmp
mtu
ttl
snmp

simple network management protocol

cat5e

the only cable you probably want to use

Resources

This could become a short ebook: DevOps Practical Guide to Modern Linux Networking