= Cheatsheet Networking =

**Summary**: A cheatsheet to collect various information regarding networking. \\
**Date**: 3 January 2025 \\
{{tag>cheatsheet network cisco}}

== 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 ===
<code>
config t
int g0/12

enter your changes

end
show run (optional to check your changes)
write
</code>

^ 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 ===

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

^ 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 |

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

^ 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:

<code>
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
</code>

== From Windows ==

> Reverse loopup with ping
<code dos>
ping -a 10.10.10.10
</code>
\\
> NSlookup with default nameserver
<code dos>
nslookup servername
</code>
\\
> NSlookup with non-default nameserver ns01
<code dos>
nslookup servername ns01
</code>
\\
> Remote desktop console
<code dos>
mstsc.exe /v:servername /admin
</code>
\\
>Test connection
<code powershell>
Test-NetConnection -InformationLevel "Detailed" -Computername $host
</code>

== Windows TCP Dump ==

Note: This needs (portable) tcpdump, the created file can be opened by (portable) wireshark for analysis. See [[https://opensource.com/article/18/10/introduction-tcpdump|here]] for more info on tcpdump.

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

== Remote IPConfig ==

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