For questions on connecting devices together so that they can communicate with each other, as well as on networking equipment such as routers and switches.

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45
votes
4answers
26k views

Is there a way to find out what application using most of bandwidth in Linux?

I'm looking for an utility that could show me how much of a bandwidth each process are using. It should just print the data and exit as I want to feed that list into conky.
43
votes
4answers
6k views

Do web browsers use different outgoing ports for different tabs?

In a web browser that supports having multiple tabs, such as Firefox, do different tabs that go to different website domains use a dedicated port for each domain?. Or does the browser use a single ...
42
votes
4answers
4k views

What is the actual speed of SATA 3?

Google says it is running at 6Gb/s. The throughput is at 600MB/s. 600MB/s equals 4.8Gb/s. Does this mean that the bandwidth is 6Gb/s but the actual throughput is 4.8Gb/s ?
42
votes
2answers
37k views

Why is my localhost not 127.0.0.1 but ::1, and what notation is that? [duplicate]

When I use the Ping command against my localhost (on Windows Vista), it doesn't show up as 127.0.0.1. C:\Windows\system32>ping localhost Pinging GIGA [::1] from ::1 with 32 bytes of data: ...
41
votes
7answers
33k views

What is a external reliable IP address to ping to check if internet is available? [closed]

Is there any common always up server, which I can setup to ping in automatic mode to detect internet is available? Like Google or something? May be 8.8.8.8? My specific situation is that I am using ...
41
votes
3answers
109k views

How can I clear the IP address of Ethernet interface without cycling the interface up/down or restarting it

What is the Linux command to clear IP address of an interface without bringing it down and/or restarting network services. Seems strange ifconfig is able to change IP address but has no option to ...
41
votes
2answers
35k views

How to launch a command on network connection/disconnection?

I have a wifi connection that requires to authenticate using a web form once the wireless link is established. I know how to automate the authentication with a script that uses curl/curlIE. But how ...
41
votes
5answers
24k views

How to use different network interfaces for different processes?

I have two network interfaces on a Linux PC, and I need to manually set the interface that a given process will use. The program (Twinkle softphone) does not have a similar option, so I believe that ...
40
votes
3answers
4k views

What's 24 in “192.168.15.0/24”?

What's the meaning of /24 in the following command? route add -net 192.168.15.0/24 192.168.8.10
40
votes
3answers
38k views

Difference between host name and domain name

What's the difference between Hostname and Domain name? especially in regards to NIC Could someone please elaborate with examples as this concept is a little confusing
39
votes
8answers
203k views

How do you automatically detect a new network card in CentOS 6 / RedHat?

I'm using CentOS 6 in a virtual environment. When cloning a virtual version of CentOS, the old eth adapters are "removed" and replaced with new ones and net MAC addresses. However, the ifcfg-ethn ...
39
votes
3answers
25k views

How to go to remote directory in Cygwin?

I'm using the latest version of Cygwin to try to cd into a network drive on Windows XP Pro Service Pack 3. The path in Windows Explorer to this directory is something like: \\myserver\photos\original ...
39
votes
2answers
97k views

How to share any folder without password in Windows 8/10 in a home network if a Microsoft account is involved?

My question is: How to set up file sharing correctly, in a home network, with Windows 8/10, so sharing any folder with "Everyone" (File Explorer->Right click on folder->Properties->Sharing->...
39
votes
8answers
6k views

Why am I getting 950 Mbps up but only 360 Mbps down on Gigabit Ethernet?

I got two desktop computers talking to each other directly. They both have Gigabit Ethernet capable network adapters. That's 1 Gbps or 1000 Mbps. I have them connected with a brand new 10 meter long ...
38
votes
3answers
115k views

What's the difference between RDP vs VNC?

What's really the difference between the RDP and VNC? They both provide the same function and features?
38
votes
5answers
2k views

What keeps you from changing your public IP address and wreaking havok?

An interesting question was asked of me and I did not know what to answer. So I'll ask here. Let's say I subscribed to an ISP and I'm using cable internet access. The ISP gives me a public IP address ...
35
votes
4answers
6k views

How smart is my network?

There is an argument within my office about how smart/efficient the network we have set up really is. We have a fibre line and a cable line running into a load balancing router, which has a hardware ...
35
votes
5answers
58k views

Can admins monitor my activity locally even when I use a VPN?

My school has one of those super overreacting web blockers (specifically Fortisnet) that blocks things that should be accessible by a high-school senior trying to research projects. Despite many ...
34
votes
5answers
3k views

What stops an internet router from sniffing my traffic?

Packets travel through internetworks, and take many routes through internet routers. On each route that forwards traffic to another until reaching the ultimate destination, what stops them from ...
34
votes
1answer
3k views

65536 +1 Connection on a system

There are 65536 ports for every system in the network, and every connection or Send/Receive will use one of those. My question is: what happens if we have 65536+1 connections?! I know that it ...
34
votes
3answers
20k views

Use a smartphone as a Dial Up Modem?

Most cellphones today have an audio jack that works as both output and input for sound. That's why there's headphones today with built in microphones for making phone calls. Now then, is it possible, ...
33
votes
1answer
31k views

Mac Wireshark alternatives [closed]

Do you know any good alternatives for wireshark (network analyzer) running on a Mac OS X 10.5+? Wireshark is not that handy like on an Windows OS (user interface with X11, ...). Any kind of help is ...
32
votes
10answers
26k views

Can I make two wireless routers communicate using the wireless?

I want to make a setup like this: cable modem <-cable-> wireless router 1 <-wireless-> wireless router 2 in another room <-cables-> PCs in another room Basically, I want to extend my ...
32
votes
1answer
4k views

What happens to TCP connections when I remove the ethernet cable?

For a TCP connection, when I remove the cable and reconnect after 30-40 seconds there is no packet loss issues. But when the reconnect time is more than a few minutes all the packets are lost. I know ...
32
votes
12answers
146k views

Windows 7 intermittently drops wired Internet/LAN connection

In a nutshell, my Windows 7 Ultimate PC intermittently drops its Internet connection. Why? Background: My PC is wired to my ADSL modem/router which is directly connected to the phone line. I also ...
32
votes
2answers
16k views

Are MAC addresses unique when coming out of the factory?

According to Wikipedia: A Media Access Control address (MAC address) is a unique identifier assigned to network interfaces for communications on the physical network segment But how unique are ...
31
votes
2answers
84k views

What is Windows command to convert machine name to ip address and vice versa?

I need to know the ip address of another machine in a lan network. What is the Windows command for getting ip address from machine name and vice versa?
31
votes
6answers
97k views

What is a subnet mask, and the difference between a subnet mask of 255.255.255.0 and 255.0.0.0?

My DSL/WiFi router provided by my ISP has an internal IP address of 10.0.0.138, the addresses provided by DHCP are in the format of 10.0.0.xxx. Now, I want to start using static IP addresses on my ...
31
votes
5answers
3k views

How do I tell Windows to use 802.11 in preference to 3G?

I have a Samsung NC-10 netbook which I take to work every day. Most of the time I use it just on the train/bus, but I also use it at work and home. It has a built-in 3G card which I want to use when ...
31
votes
5answers
20k views

How do I physically find a wifi device using a laptop or mobile phone

Okay, so I have lost my tablet somewhere in my flat and have been searching for hours already. It is an Android device, which seems to have wifi enabled (responds to pings), but doesn't seem to react ...
30
votes
2answers
51k views

How can I change the default website connection timeout in Chrome?

I want to change the default timeout in Chrome. In Firefox I can set the value of network.http.connection-timeout in about:config - but how can I do that in Chrome?
30
votes
5answers
20k views

How do CDN (Content Distribution Networks) work?

Taking Akamai as CDN. From what I understand, when a client requests a page, the request goes to Akamai central server, which then depending on the location of client, picks up an Akamai edge server ...
30
votes
4answers
6k views

Why is ping faster through VPN than without a VPN?

When I play an online game without VPN, the ping is around 120ms. But when I use VPN with a virtual location in Germany, the ping is only 60-70ms (which is amazing). When I use virtual location to ...
30
votes
7answers
36k views

Force an application to use a specific network interface

I'm using multiple network interfaces (LAN and Wireless), and I've noticed that there's a way to change the order of prefered interfaces. How can I use the wired network to do work, check email, and ...
29
votes
9answers
188k views

How can I ping a range of IP addresses simultaneously [closed]

I have a bunch of machines on an IP address range which I want to ping simultaneously as a quick and dirty way of telling which ones are switched on. What (free) software can I use to do this? I'm ...
29
votes
5answers
15k views

Are Domain Name Server and Name Server the same thing?

I am slightly confused between DNS and Name server. Are they the same thing or is there a difference between two?
29
votes
2answers
52k views

What is the difference between NAT / Bridged / Host-Only networking?

VMWare: What is NAT vs. Bridged vs. Host-Only?
29
votes
10answers
14k views

Application for monitoring all applications that are using the internet in Mac OS X

Can anyone introduce me a Mac OS X application that monitors all network activity such as what applications are now connected to the internet and how much bandwidth they use (I mean show bandwidth ...
28
votes
7answers
134k views

How to force Windows 7 to ask for a “fresh” IP address from DHCP server?

I'm troubleshooting a certain issue with my DHCP configuration, and need my Windows machine to ask for a "fresh" IP address, so I can see which address DHCP server gives by default. When I do ...
28
votes
7answers
94k views

Display list of computers on a LAN in Linux

I'm a web dev who is trying to get a better handle on security. I'm trying to figure out a way (on Linux/Debian based distros) to list all computers on the same LAN my netbook is on. I tried "arp -n" ...
28
votes
2answers
28k views

How to get VirtualBox VMs to use host's DNS?

I use VirtualBox for my VMs. My office network setup is wireless, i.e. I connect to my company's WiFi network, which has a local DNS to resolve local names (such as something.mycompany.com going to ...
28
votes
3answers
281k views

What is the Teredo Tunneling Pseudo-Interface?

I am running Windows 7 Ultimate, and when I do ipconfig /all in the command prompt I get, in addition to the Ethernet adapter Local Area Connection that I expected, something called Tunnel adapter ...
28
votes
9answers
24k views

Parallelizing rsync

I just moved and discovered after some trial and error that somewhere between my home and my remote server, there is some throttling going on...but the throttling is not very intelligent. It only ...
28
votes
3answers
41k views

What is the relevance of “fe80::1%lo0 localhost” in /etc/hosts?

Following are the entries in my /etc/hosts. I was wondering what is the last entry (fe80::1%lo0 localhost) for. 127.0.0.1 localhost 255.255.255.255 broadcasthost ::1 localhost fe80::1%lo0 localhost
27
votes
5answers
4k views

Why do similar devices use a cross-over cable instead of a straight-through cable?

Why do similar devices use a cross-over cable instead of a straight-through cable?
27
votes
6answers
85k views

Why does just splitting an Ethernet cable not work?

I thought the Ethernet is logically a one-line communication bus (for argument's sake, I am excluding hubs). All machines attached on the bus hears the same signals and the machines themselves try to ...
27
votes
10answers
3k views

Does speed enhancement software actually work? [duplicate]

Here on the Internet, we see many ads promoting software products which can enhance your Internet speed. I wonder, how could this be? Imagine that you are using a 1 Mbps Internet connection, and the ...
27
votes
9answers
128k views

How can I monitor internet usage in my network?

I need to know which computer is consuming my bandwidth. Is there a tool to do this?
27
votes
7answers
66k views

Why can I ping an IP address but not 'traceroute' it?

I can ping an IP address, but I can't traceroute it. How could this be? [USERNAME@HOSTNAME ~]$ ping CENSORED.CENSORED PING CENSORED.CENSORED (CENSORED) 56(84) bytes of data. 64 bytes from CENSORED....
27
votes
2answers
12k views

How do you get loopback addresses other than 127.0.0.1 to work on OS X

According to everything I read, the entire 127.x.x.x subnet should loopback. However, on my Mac, I can only ping 127.0.0.1 I know I've done this before (though possibly on another OS) and has come ...