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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 ...
grawity_u1686's user avatar
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 ...
NetwOrchestration's user avatar
60 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 ...
nisetama's user avatar
  • 1,069
58 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 ...
kasperd's user avatar
  • 2,901
57 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 ...
ralz's user avatar
  • 2,528
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 ...
user4556274's user avatar
  • 1,420
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 ...
Blackwood's user avatar
  • 3,173
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 ...
davidgo's user avatar
  • 71.4k
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 ...
Vilx-'s user avatar
  • 4,217
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 ...
Andrew Leach's user avatar
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 ...
Dan's user avatar
  • 693
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 ...
Spiff's user avatar
  • 106k
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 ...
grawity_u1686's user avatar
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 "...
Albin's user avatar
  • 10.9k
21 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 ...
ctrl-alt-delor's user avatar
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 ...
Frank Thomas's user avatar
  • 36.4k
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 ...
grawity_u1686's user avatar
18 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 ...
Pau Coma Ramirez's user avatar
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 ...
John Burton's user avatar
18 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 ...
Mikael Kjær's user avatar
  • 1,533
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 ...
davidgo's user avatar
  • 71.4k
17 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 ...
Daniel Karrenberg's user avatar
15 votes

What is the purpose of 192.168.1.0?

x.x.x.0 traditionally is a broadcast address. (Was later changed to x.x.x.255) It will forward your request to all ipaddresses in the range 1/254, but only if the OS supports it. By default on OSX and ...
LPChip's user avatar
  • 62.3k
12 votes

What is the difference and relationship between a process id and a port number?

The PID is shown only so that you can identify the specific process doing the communication and is unrelated to the port number. If you had multiple copies of one program running and they were all ...
Mokubai's user avatar
  • 93.8k
11 votes
Accepted

Change public IP address

If your router is assigned an IP address by your Internet Service Provider (ISP) via the Dynamic Host Configuration Protocol (DHCP), you may be able to force a change in the external IP address ...
moonpoint's user avatar
  • 5,208
11 votes

How do I get cells in Excel that contain IP addresses to sort properly?

The most easiest, 3 steps Solution I can suggest you are,,, Select the IP Address Column, apply Text to Column command. In adjacent Column write this Formula =CONCATENATE(B3,".",C3,".",D3,".",E3) ...
Rajesh Sinha's user avatar
  • 9,274
11 votes

Is it possible to see my external IP address without making an outbound web request?

There are a few ways that work with some NATs but nothing that's guaranteed to work everywhere. I believe uPnP, NAT-PMP, and PCP (Universal Plug And Play, NAT Port Mapping Protocol, and the Port ...
Spiff's user avatar
  • 106k

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