Question: I am currently working on connecting ip cameras together .
I am using cat7 sftp cable .

according to the bellow article :

<http://www.differencebetween.net/technology/difference-between-rj45-and-rj48/>

I understand that :

1. RJ45 is used with UTP cable only .
2. I can't use RJ48 because it will not fit into my NVR and SWITCHES .

I have two questions :

1. I found RJ45 which fit cat7 cable .

[https://www.amazon.com/dp/B071GXPTVZ/ref=twister\_B09ZYBKJFZ](https://rads.stackoverflow.com/amzn/click/com/B071GXPTVZ)

How could that happen ? RJ45 should be used with utp cables only ? right ?

2. what's the right connector to choose to connect cat7 sftp to ip camera ?

some people suggest to connect Cat6a Cat7 Keystone at the end of cat7 cable .

[https://www.amazon.com/dp/B074PKQ1S1/](https://rads.stackoverflow.com/amzn/click/com/B074PKQ1S1)

then to use short cat 6 cable to connect between the keystone and ip camera .

is that the correct method ?

Thank you

Answer: 
> 
> Why do we need ports with IPv6?
> 
> 
> 

As Zac67 already said, it was intended to make IPv6 as compatible to IPv4 as possible to ensure that existing programs need not to be changed too much.

Keep in mind, that in IPv4, the destination port of a TCP connection also specifies the type of higher-layer protocol:

80 for HTTP, 443 for HTTPS, 23 for Telnet and so on.

So we need the TCP port in IPv6 as indication of the higher-layer protocol type if we want to be compatible to IPv4.

> 
> Why not assign each application, tab, etc... its own public IPv6 address
> 
> 
> 

I was already thinking about this: Doing this would allow implementing certain additional security and privacy features. So I can imagine that this will actually be done in the future.

And of course: We can get rid of URLs like `https://example:8443/`: Instead of using different ports (8443) on server side, we can simply use multiple IPv6 addresses.

However, it would still not allow us to get rid of the source port of a TCP connection:

I rembember some web-based application that requires two HTTP(S) connections to be established between the client and the server at the same time.

In this case, the server will surely check if both connections come from the same client (this means: same source IP address).

However, this means that both connections have the same two IP addresses and the same destination port (443 in the case of HTTPS). Therefore, they must have a different source port.

And if IPv6 should be compatible with IPv4, this web-based application must work the same way with IPv6 as it works with IPv4.
Frame Challenge: Once The ports are folded into IP addresses, you'll be burning IP addresses for a singular device, and run the risk of actually running out of IP addresses.
=============================================================================================================================================================================

Currently in IPv4, the number of valid ports is 65,535 - but 0 - 1023 are restricted or reserved port numbers (Often reserved by specific company processes as well - for example, apparently [Apple QuickTime, and Remote Desktop Protocol](https://www.techtarget.com/searchnetworking/definition/port-number) does.

Natural Address Translation takes advantage of the fact that, for most users, which unrestricted and unreserved port being used generally doesn't matter for the average use case, and doesn't need to be aligned between client and server, so we can re-map them. But what made it required to be a thing that we went with was that IP address blocks were bought by companies in large, "We'll never run out of numbers to assign!", well...numbers. Large enough *to* run out.

On top of this, once machines move around and switch ISPs, then they would run through more IP addresses, and their previous one would have to be *expired* when routing to them.

With a single IP address per machine, you can "keep" that old IP address assigned to that older device, even if it temporarily leaves where it was assigned the IP address from for a short time (More likely to be a mobile machine, or a laptop), and keeping those lower will help.

Granted, 2^128 is a *lot* of IP addresses, but ports will allow us to avoid running into a similar version of the problem with IPv4 thinking it had more than enough IP addresses for everyone and their dog.