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Notes code can be run in Jupyter NoteBook (actually Jupyter-lab experience is great).
Recommended not to look, to be more hands to knock code. Eye over a thousand was better to hand read it again.
Jupiter run code related notes have been uploaded, downloaded from your own resources.
Network Analysis Tool
wireshark
Problems may arise under linux: insufficient permissions to open wireshark tips
Solution:
Reference Site
Add Group, wireshark, but when you install the software has been created here can be omitted
sudo groupadd wireshark
Add yourself to the group wireshark
sudo usermod -a -G wireshark 'username'
newgrp wireshark
Change Group
sudo chgrp wireshark /usr/bin/dumpcap
Adding permissions (1-x, 2-w, 4-r)
sudo chmod 754 /usr/bin/dumpcap
Here the author has two methods, I chose a simple
sudo setcap cap_net_raw,cap_netadmin=eip /usr/bin/dumpcap
sudo reboot now
So far, the problem is solved
Packet Tracer
** Hub (hub) ** link multiple computers to complete the
transmission of each data packet is carried out as broadcast, network easily clogged
Switch to complete a plurality of linked computer
transmits each packet is carried out as broadcast, network easily clogged
if the PC unknown MAC destination IP corresponds, then it can be seen, pc arp broadcast transmission will first give the other side of the MAC and then, during data transfer
when first received switch arp broadcast data forwarding will arp broadcast packets to all ports (except the source port); if there pc after asking this IP-MAC, then just forwards the data to the destination port
** router (Router) ** known as a gateway device (Gateway) is a network for connecting the plurality of logically separate
Pc in the same network segment, you need to set the default gateway to the past data transfer Typically, the router will be the default gateway
when a router receives a packet from other segments, will be determined according to "routing table" to this data packet to which port; routing table setting static and dynamic methods
each time through the router, it will decrease the value of a TTL
Ciso of packet tracer
HUB hub now substantially obsolete now generally used in the switch
Router: links to different segments of the network, the device can communicate with different segments
mac address in the communications transmission, is dynamic, then change occurs between two devices
IP address of the communication transmission, is static, it does not change throughout the transmission
