Unannounced Visit Investigation Forensics Special Equipment
Whether installing a network security surveillance camera or a computer network, We have to mention a well-known term, that is “IP address”, in the third layer (network layer) of the computer network OSI seven-layer protocol, we know that the connection establishment, termination and maintenance between computers, etc., data packets The selection of transmission paths and so on are inseparable from “IP addresses”. However, if you study computer networks, do you know the meaning of these IP addresses? Now let me tell you slowly.
One . 0.0.0.0
Strictly speaking, this weird address 0.0.0.0 is no longer a real IP address. It represents such a set: that is to say; all unknown hosts and destination networks. “Unclear” here means that there is no specific entry in the local routing table to indicate how to get there. This machine is a “shelter”, and all the “three noes” people who don’t know will be sent there. If you set the default gateway in the network settings, the computer system will automatically generate a default route with the destination address 0.0.0.0.
Two . 255.255.255.255 restricts the broadcast address.
For this machine, this address refers to all hosts in this network segment (same broadcast domain).
However, its meaning is very clear. In human language, it means “All computers here pay attention.” This address cannot be forwarded by routers.
Three, 127.0.0.1 local machine address
Mainly used for testing. In Chinese, it means “myself”. On Windows systems, this address has an alias “Localhost”. To address such an address, it cannot be sent to a network interface. A packet with a destination address of “127.0.0.1” should never appear on the transport medium unless something goes wrong.
Four. 22.214.171.124 multicast address
Note the difference between it and broadcast. This is the address from 126.96.36.199 to 188.8.131.52. 184.108.40.206 refers to all hosts, and 220.127.116.11 refers to all routers. Such addresses are mostly used for specific programs and multimedia programs. If your host has enabled IRDP (Internet Route Discovery Protocol) and uses the multicast function, then there should be such a route in your host routing table.
If your host uses the DHCP function to automatically obtain an IP address, then when your DHCP server fails, or the response time is too long and exceeds the time specified by a system, the computer operating system will assign you such an address. If you find that your host IP address is one of these, unfortunately, your network security camera is now not functioning properly.
Six, 10.x.x.x, 172.16. x. x ~ 172.31. x. x, 192.168. x. x private address
These addresses are widely used in corporate internal networks. Some broadband routers also often use 192.168.1.1 as the default address. Since the private network is not interconnected with the outside world, it may use random IP addresses. Such address is reserved for its use to avoid address confusion when accessing the public network in the future. When a private network using a private address accesses the Internet, address translation (NAT) is used to translate the private address into a public legal address. On the Internet, such addresses cannot appear. For a host on a network, there are three legal destination network addresses that it can normally receive: the local IP address, broadcast address, and multicast address.
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