304
votes
Accepted
What's the difference between 127.0.0.1 and 0.0.0.0?
What's the difference between 127.0.0.1 and 0.0.0.0?
127.0.0.1 is the loopback address (also known as localhost).
0.0.0.0 is commonly used as a non-routable meta-address used to designate an invalid,...
- 152k
125
votes
What's the difference between 127.0.0.1 and 0.0.0.0?
They are not the same.
127.0.0.1 is part of the 127/8 network which is reserved and points to the same computer.
0.0.0.0 is a special IP address that means different things depending on context.
In ...
- 1,231
93
votes
Accepted
In a symlink pointing to '127.0.1.1:+xxxxx', what is the plus character for?
Symbolic links which don't point to a file have no generic meaning at all. In this case it might be the process ID, or a port with some special protocol spoken over it, or another identifier. It all ...
- 415k
62
votes
Accepted
How can every single device on a network have a different public IP?
They own an IP range, and are using the range to directly connect to WAN (Internet) instead of hiding behind NAT (Network Address Translation). Basically, NAT was made for environments lacking enough ...
- 3,175
56
votes
Can someone please explain ifconfig output in Mac OS X?
You can see the names that are used in System Preferences for some of the devices by running networksetup -listallhardwareports:
Hardware Port: HUAWEIMobile-
Device: HUAWEIMobile-Modem
Ethernet ...
- 1,021
56
votes
Accepted
Do 'dumb' (non-smart, non-managed) switches have an IP address?
An unmanaged switch does not even know what IP is. It will forward IP packets as well as many other protocols without ever understanding what the difference is.
All the switch needs to know in order ...
- 2,861
51
votes
Accepted
What is my actual IP address?
Your internet provider is using Carrier grade NAT. Your local (to your house) IP address is 192.168.x.x. Your local (to your ISP) address is 10.230.x.x. The public, routable IP which you are ...
- 1,400
51
votes
Accepted
What does a forward slash followed by a number mean in IP?
It indicates the subnet mask of the IP.
IP has 32 bits, and number after the slash tells you where does the network part end, host part starts.
IP 10.39.25.151 written in binary format looks like ...
- 2,470
45
votes
Pinging different IP address than what I entered
On Windows CMD if you put leading zeros on the IP address means octal.
It is interpreting 016 as 16 octal and converts it to 14 decimal.
You can use octal, decimal or hexadecimal notation as in the ...
- 17.1k
42
votes
Accepted
How do I get cells in Excel that contain IP addresses to sort properly?
As you may have realised, your IP addresses are treated as text and not numbers. They are being sorted as text, which means that addresses beginning with "162" will come before addresses beginning ...
- 3,103
42
votes
Accepted
How does DNS work when it comes to addresses after slash?
When it comes to handling http(s) requests, all that DNS does is convert the domain name to an IP address. The web browser then connects to that IP address and asks for the resource (eg part after ...
- 67.6k
39
votes
How does DNS work when it comes to addresses after slash?
To add to the other answers: here's a quick dissection of a URL:
https://www.example.com:99/some/path?a=b&c=d#1223
https:// - the protocol aka the "language" that the browser will use ...
- 4,105
36
votes
Accepted
What is the difference and relationship between a process id and a port number?
To answer the question directly: there is no connection between the process ID and the port number. They enumerate entirely different things.
The PID identifies a process (eg a Firefox session: each ...
- 553
36
votes
Accepted
My IP addresses changed from 192.168.2.xxx to 192.168.1.xxx. I can't reach the switch anymore
Temporarily change one of your computers' IP address to be in the 192.168.1.0/24 range and you should be able to connect to your switch (you will be disconnected from the Internet). Then just ...
- 663
27
votes
How to access 192.x address space from 10.x address space?
It sounds like you have more than one NAT gateway on a small network. Doing “Double NAT” — as this is called — usually causes several hassles, just one of which is the one you’re experiencing: part of ...
- 100k
24
votes
Is it possible to see my external IP address without making an outbound web request?
If your computer is behind NAT, it is possible for you to see the external IP address
of your router, but you need administrative access to the router.
The router knows your external IP address, so ...
- 444k
24
votes
Can an ISP see private IP addresses?
But does that happen with private IPs also? I mean, like, the ISP of the wifi router sees and keeps a log about exact which packets from which website is being sent to which eaxct device connected to ...
- 415k
22
votes
In a symlink pointing to '127.0.1.1:+xxxxx', what is the plus character for?
As far as I know the "+" means that the number after the IP (the "xxxxx") refers to a "process ID" (not a port which usually uses the notation [IP-address]:[portnumber]).
It is possible that this "...
- 9,069
20
votes
Accepted
Why is ip address listed as 172.18.0.150/24?
Some IP address basics
IP addresses are internally represented as a 32 bit value. The topmost N bits identify the network, the rest of the number identifies the host in the network.
Let's look at ...
- 4,849
19
votes
How can every single device on a network have a different public IP?
Back in the old days (before the Public Internet came into being in 1991), technologies like NAT were not common, and most operators did not use RFC1918 addresses. They didn't divide the Internet into ...
- 34.6k
19
votes
Accepted
Does it matter which static IP address I choose for my devices?
Technically it makes no difference what IP address your device has.
Usually consumer/home routers will set the DHCP range to be high numbers, ie. 100 to 200 in which case it makes sense to put static ...
- 1,503
19
votes
How does DNS work when it comes to addresses after slash?
what if the address after the slash has a different IP address?
It literally never has a different IP address. The HTTP URL syntax doesn't make that possible; it defines that only the part up to the ...
- 415k
18
votes
What is Windows command to convert machine name to ip address and vice versa?
in window 7 and later versions.
to find ipv4 ip by hostname you can try following methods.
For ipv4 (192.168.1.2):
ping hostname -4
For ipv6 (0000:0000:0000:0000:0000):
ping hostname -6
18
votes
What's the difference between 127.0.0.1 and 0.0.0.0?
127.0.0.1 is one of the addresses of local computer, but any address 127.x.y.z also is another address of the computer (called "loopback address"), except 127.0.0.0 (loopback subnet) and 127.255.255....
- 405
18
votes
How can every single device on a network have a different public IP?
This is how the internet is supposed to work.
People started using private address ranges and NAT because the number of spare IP addresses started to get used up. And then people found that using NAT ...
- 442
18
votes
Can an ISP see private IP addresses?
The simple answer is "not in most cases" - however the total answer is a lot more nuanced.
In the common case where a router is doing NAT, and where the ISP has no login to the router and ...
- 67.6k
17
votes
What is the 127.0.0.2 IP address for?
I will answer each of your questions below, with references and examples. It is not as simple as Yes or No.
“Are all 127.x.x.x addresses restricted to the local machine?” Yes
“Are all 127.x.x.x ...
- 2,326
17
votes
How can I specify IP and ports for a hostname in the Windows hosts file?
The hosts file is for resolving hostnames to IP addresses only
If you do not specify a port as part of a URL, e.g. <protocol>://<hostname>[:<port>][/path], your browser will use the ...
- 523
16
votes
Why did the IETF specifically choose 192.168/16 to be a private IP address class?
The RFC explains the reason why we chose three ranges from "Class A,B &
C" respectively: CIDR had been specified but had not been widely
implemented. There was a significant amount of equipment ...
Only top scored, non community-wiki answers of a minimum length are eligible