Cheatsheet Networking

Summary: A cheatsheet to collect various information regarding networking.
Date: 3 January 2025

OSI Model

Layer Type	Data Unit	Layer	Function	Example
Host Layer	Data	7. Application	Network process to application	DNS, FTP, HTTP, NFS, NTP, SMTP, SNMP, Telnet
Host Layer	Data	6. Presentation	Data representation and encryption	MIME
Host Layer	Data	5. Session	Interhost communication	NetBIOS
Host Layer	Segment	4. Transport	End-to-end connections and reliability	TCP, UDP, SSL, TLS
Media Layer	Packet	3. Network	Path determination and logical addressing	IP, ICMP, IPsec, IPX, AppleTalk
Media Layer	Frame	2. Data Link	Physical addressing	ARP, Ethernet, PPP
Media Layer	Bit	1. Physical	Media, signal and binary transmission	T1, DSL, 802.11a/b/g/n PHY, Ethernet, USB, Bluetooth

Cisco

This is a notes page, extended with tips & tricks. This page is not really documentation, just stuff for me to remember. Sometimes things will get removed from these pages and turned into real documentation, sometimes not. You might find these notes to come in hand, maybe not. For me, it's just things I don't want to forget.

Log In

config t
int g0/12

enter your changes

end
show run (optional to check your changes)
write

Command	Description
conf t	config terminal ; configure via terminal
int g0/12	interface g0/12 ; configure gigabit interface of stack 0, port 12
end	ready with changes
write	save the changes

Settings

interface GigabitEthernet0/12
 description server12
 switchport access vlan 10
 switchport mode access
 spanning-tree portfast
 spanning-tree bpdufilter enable
 no shutdown

Setting	Beschrijving
description server12	Description given to the port
switchport access vlan 10	The vlan the port has access to
switchport mode access	There is just one vlan where the port has access to
spanning-tree portfast	Fast availability despite spanning-tree
spanning-tree bpdufilter enable	Prevent broadcast packet storms
no shutdown	Enable the port

interface GigabitEthernet0/4
 description blade4
 switchport trunk native vlan 3999
 switchport mode trunk
 spanning-tree portfast trunk
 spanning-tree bpdufilter enable

Setting	Beschrijving
switchport trunk native vlan 3999	Devices without a vlan tag will be in this vlan
switchport mode trunk	The port has access to all vlans, vlan tagging is done on device level
spanning-tree portfast trunk	Fast availability despite spanning-tree

Fast Overview All Ports

The show interfaces status command will give you a quick overview of port configuration:

coreswitch#show interfaces status

Port      Name               Status       Vlan       Duplex  Speed Type
Gi1/0/1                      connected    trunk      a-full a-1000 10/100/1000BaseTX
Gi1/0/2                      connected    trunk      a-full a-1000 10/100/1000BaseTX
Gi1/0/3                      connected    trunk      a-full a-1000 10/100/1000BaseTX
Gi1/0/4                      connected    trunk      a-full a-1000 10/100/1000BaseTX
Gi1/0/5                      notconnect   18           auto   auto 10/100/1000BaseTX
Gi1/0/6                      notconnect   1            auto   auto 10/100/1000BaseTX
Gi1/0/7                      notconnect   1            auto   auto 10/100/1000BaseTX
Gi1/0/8                      notconnect   1            auto   auto 10/100/1000BaseTX

From Windows

Reverse loopup with ping
ping -a 10.10.10.10

NSlookup with default nameserver
nslookup servername

NSlookup with non-default nameserver ns01
nslookup servername ns01

Remote desktop console
mstsc.exe /v:servername /admin

Test connection

Test-NetConnection -InformationLevel "Detailed" -Computername $host

Windows TCP Dump

Note: This needs (portable) tcpdump, the created file can be opened by (portable) wireshark for analysis. See here for more info on tcpdump.

dump traffic with host 10.10.10.10 on interface 1 to file
\tcpdump.exe -i 1 -vv host 10.10.10.10 -w tcpdumpfile.pcap

dump traffic with host 10.10.10.10 on interface 1 to file with a readable timestamp format
\tcpdump.exe -i 1 -vv host 10.10.10.10 -tttt -nr tcpdumpfile.pcap

Remote IPConfig

Renew Ip config remotely without losing access
ipconfig /release && ipconfig /renew

wiki.getshifting.com

Table of Contents