wired-networking interview questions
Top wired-networking frequently asked interview questions
I have a 10 meter long Ethernet cable. One plug has the little locking clip missing, just like missing the part in red ellipse in the following picture.
How can I fix it? Is this something I should even attempt to fix myself, or is it better to replace the cable?
Source: (StackOverflow)
I have a very simple question: if I have a router (DHCP enabled - leasing IP addresses between 192.168.0.2 and 192.168.0.254) with a switch plugged in, and I plug two computers into the switch, will the network traffic (file transfers etc.) be sent through the router, or will it simply go straight through the switch to the other computer completely avoiding the router?
Source: (StackOverflow)
I'm having trouble getting my Ubuntu 10.04 machine (Sony Vaio VGN-SR490) to connect to the Internet by way of an Ethernet cable connected directly to my router.
I'm able to connect to the Internet using this same cable using a Windows machine, so there's something wrong with the way Linux is configured.
How do I got about figuring out what the problem is and solving it?
Here are my network settings on Linux:
$ ifconfig
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
vmnet1 Link encap:Ethernet HWaddr 00:50:56:c0:00:01
inet addr:192.168.79.1 Bcast:192.168.79.255 Mask:255.255.255.0
inet6 addr: fe80::250:56ff:fec0:1/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
vmnet8 Link encap:Ethernet HWaddr 00:50:56:c0:00:08
inet addr:192.168.192.1 Bcast:192.168.192.255 Mask:255.255.255.0
inet6 addr: fe80::250:56ff:fec0:8/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
Here are my network settings on Windows (Vista):
Ethernet adapter Local Area Connection:
Connection-specific DNS Suffix . : [removed by me].
Link-local IPv6 Address . . . . . : [removed by me]
IPv4 Address. . . . . . . . . . . : 192.168.1.103
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.1.1
I censored my IP address from these results. If that information is needed, just let me know.
Here is the content of /etc/network/interfaces:
auto lo
iface lo inet loopback
After adding auto eth0, here are the latest results:
$ sudo ifup eth0
Internet Systems Consortium DHCP Client V3.1.3
Copyright 2004-2009 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/
SIOCSIFADDR: No such device
eth0: ERROR while getting interface flags: No such device
eth0: ERROR while getting interface flags: No such device
Bind socket to interface: No such device
Failed to bring up eth0.
Here are the results of running a modprobe:
$ sudo modprobe msk
FATAL: Module msk not found.
$ dmesg | grep eth
I removed Linux from my computer and installed Windows XP, at the request of some of the people commenting on this question. I installed an ran a program to find out details about the network card. Here is that information:
Network
You are not connected to the internet
Computer Name
NetBIOS Name JOE-LAPTOP
DNS Name joe-laptop
Domain Name joe-laptop
Remote Desktop
Console
State Active
Domain joe-laptop
RDP-Tcp
State Listen
WinInet Info
An internal error occurred.
Wi-Fi Info
Wi-Fi not enabled
WinHTTPInfo
WinHTTPSessionProxyType No proxy
Session Proxy
Session Proxy Bypass
Connect Retries 5
Connect Timeout 60000
HTTP Version HTTP 1.1
Max Connects Per 1.0 Servers INFINITE
Max Connects Per Servers INFINITE
Max HTTP automatic redirects 10
Max HTTP status continue 10
Send Timeout 30000
IEProxy Auto Detect No
IEProxy Auto Config
IEProxy
IEProxy Bypass
Default Proxy Config Access Type No proxy
Default Config Proxy
Default Config Proxy Bypass
Adapters List
Network Shares
No network shares
It looks like the network adapters list is empty. I will now install both Windows XP and Ubuntu Linux dual-boot. I'm still not able to access the internet, even through Windows. I'm wonder if this could be a hardware problem with the computer or a problem with the router itself. Other computers can connect to this same router, and work fine. (That's how I'm posting this after all!)
Source: (StackOverflow)
I'm looking for a way to directly connect my Windows 7 laptop and my headless Ubuntu 10.04 server. (Desktop edition is installed, for my own reasons.) I have a regular Ethernet cable. My problem is that I keep trying to use Windows Backup to a shared folder on Ubuntu, but the wifi connection keeps dropping intermittently for all my devices at the same time before the backup completes. I want to use the cable to connect the two computers directly, independent of whether or not they're connected to wifi. This will create a much more reliable connection, and it will allow the backup to complete without worrying about the wifi dropping.
It would be best if I could create this connection using an ad-hoc network (or similar) on Windows 7 without touching the configuration on the Ubuntu server, as the server has no input devices or displays connected to it. I mostly access it through SSH and sometimes VNC, and if the connection is lost, the only thing I can do to get it back is a hard reboot.
So the current configuration is this:
Windows 7-------wireless-----\
\
Wifi router
/
Ubuntu 10.04----wireless-----/
But I want it to be like this:
Windows 7-------wireless-----\
| \
|cable Wifi router
| /
Ubuntu 10.04----wireless-----/
Source: (StackOverflow)
Now I understand that my Internet speed is determined by my weakest link, which in general is based on what speed I pay for. I am looking at purchasing a new wired router and the one I want is only 100 Mbit/s, as opposed to some gigabit/s options out there so I am wondering, would the gigabit/s speed have any impact on my internal network?
See this diagram below for how I have my network configured:
I have gigabit/s hubs connecting my devices back to the router. This means that they are unmanaged of course. I am looking at getting the wired router essentially to just to do the management of assigning IP addresses. Since everything else is unmanaged up to the point of the router, will the 100 Mbit/s speed impact my network?
I am trying to learn here so if the answer is yes or no, please add some explanation as to why this is true.
Source: (StackOverflow)
I have no wired connection internet access on ubuntu 14.04 even though it is detected, my computer connected to the same router has.
$ ifconfig
eth0 Link encap:Ethernet HWaddr 4c:72:b9:7e:b5:61
inet addr:192.168.1.2 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::4e72:b9ff:fe7e:b561/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:93 errors:0 dropped:0 overruns:0 frame:0
TX packets:705 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:18292 (18.2 KB) TX bytes:76277 (76.2 KB)
Interrupt:17
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:701 errors:0 dropped:0 overruns:0 frame:0
TX packets:701 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:54442 (54.4 KB) TX bytes:54442 (54.4 KB)
wlan0 Link encap:Ethernet HWaddr 08:3e:8e:5f:56:1e
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
Source: (StackOverflow)
I'm using Windows 7 and I have 2 networks:
- one wireless with internet connection
- one wired with no internet connection
The computer is connected to both. The problem is that although in Network and Sharing center it shows that the wireless connection has internet, it also shows that the computer is not connected to the internet.
If I only connect with the wireless, I have internet connection, but when connecting to the wired one it just can't access the internet anymore. And on the wired network I also have a printer that I want to share, but I can't see it if the wireless is also connected.
I suppose that there is a setting for default connection. What I want is to be able to connect to the internet over the wireless network and also to see the shared printer over the wired network.
And very important: I don't want the users on the wired network to be able to access the internet through my PC and the wireless connection (I don't want something like a bridge).
Source: (StackOverflow)
I want to experiment with 802.1x wired authentication and I don't have a switch with such capability.
How can I quickly set up a lab for that purpose? (e.g. take a Linux machine and make it act like a switch with 802.1x wired authentication)
Source: (StackOverflow)
To run two cables (for wired computers) from a modem? My family has a DSL modem that we connect to via Ethernet and we would like to be able to use more than one wired computer on it at a time... Is this possible? If so how?
Source: (StackOverflow)
Nowadays, I usually make EIA/TIA-568A crossover cables for Fast Ethernet(10/100 Mbps) networks. On these cables, just 2 of the 4 wire pairs are used to comunications(the 2 remaining could be used for PoE or just for nothing), so I just needed to cross 2 color pairs(1-2 and 3-6 wires). However, on Gigabit Ethernet all the 4 wire pairs are used to increase the network bandwidth. So, to do a crossover on a Gigabit Ethernet I would need to cross all the 4 pairs. Is this feasible and reliable? I mean, how to make that and what is the correct color order of both ends of a Gigabit Ethernet crossover cable?
Source: (StackOverflow)
I am a university student, and I live at a student hall. My student hall, does not have WiFi, (and does not allow someone to install a router), and I only have a socket to connect to the internet by a wire.
A friend of mine will come in two days, to do a project together, and we will both need access to the internet. We both have Windows 8 installed. This is for just a couple of hours.
How I am able to connect both computers at the network with having only one socket? Is it possible to do that, but without being able for the student hall to see that I have connected two laptops?
I will just need it for a couple of hours.
Edit
Using the solution from here does not work for me. When I try to make my connection shared, then automatically my wired connection shows a "limited conenctivity" symbol, and I cannot connect at the Internet. Do I make any mistake? Is there any alternative?
Thanks a lot
Source: (StackOverflow)
I assembled a Windows 7 machine a few weeks ago, and now I noticed my download speeds are abysmal. Copying to this computer is about 150kbyte/sec, on a Gigabit LAN. Copying from it is fine.
- It is not an ISP issue, as LAN copy speeds have the same problem
- It is not a cable problem, the speed is the same on any cable
- It is not a router issue, because the other computers on the LAN have no similar problems, and I even changed the socket this computer is plugged into on the router
- It is not tied to a specific application, torrent, ftp and browser downloads are equally slow
- It is probably a driver issue, because after reinstalling the Ethernet driver the download speed went up to 500kbyte/sec for half a day
- Setting manual speed negotiation did not help either
- Installing Win 8.1 clean (not just upgrade) did not solve the issue
The NIC is a Realtek PCIe GBE Family Controller according to the Device Manager. It came with the Asrock AM1B-ITX motherboard.
The drivers were provided with the motherboard, but I tried the default Windows ones and and the latest from AMD.
Update2: *I just loaded Puppy linux, and the copy speeds were great were great for the first half hour. After that, the same behavior.
Source: (StackOverflow)
In the planning stages of a new school construction project. What is the current recommended wiring standard for this type of communication A/V heavy structure? Assuming it is Cat 6A, and all structures are wired with shielded FTP cabling, and terminated with cat6A patch panels and wall ports.
Current switches and network cards in the computers are cat5e 10/100/1000 mbps ports. Will the existing cat5e patch cords work? If not, will cat6A patch cords plug into cat5e machine ports on one end and cat 6A wall outlets and patch panels on the other end?
I have seen a few articles talking about cat 7 and cat 8 wiring? Should we be looking at those to future proof the network? IF so the above question would still apply.
Source: (StackOverflow)
I work from home and all my communication and all my home entertainment is done over IP via my home network. I'd like to take my consumer-grade home network to the next level but I'm unsure where to start.
If I wanted to move from say, consumer grade wired and wireless, to small office grade wired and wireless where would I look? Can I build a better performing, more secure and more reliable home network without going way over the top?
Currently I run a D-Link DIR-655 and it's fed in to an SMC cable modem accessing the top tier service that's available in my area from my cable company.
On my wired network I have:
- An older Vonage Linksys router (currently set to the DMZ), serves up two VOIP lines (home and office)
- HTPC running Windows XP SP3 connected via GBit ethernet, used mainly for streaming high definition Netflix and cable company on-demand services
- iMac connected via GBit ethernet
- Xbox 360 (latest generation so I think it's Gbit) via ethernet, used mainly for gaming and the occasional high definition Netflix stream
And for wireless use I have:
- 2 x 2010 MacBook Pros running OS X 10.6.7 using the N band
- 2 x iPhone 3GS (not sure what the use)
- Playstation 3 using the N band, used mainly for standard definition Netflix streaming
- HP OfficeJet 6500 E709N
On the internal network there's a fair bit of traffic to the iMac as it serves as a TimeMachine hub for the MBPros. All the Apple machines in the house stream a fairly heavy amount of outbound data at night as they do another level of back to the cloud via CrashPlan.
During the day time network traffic is typically work-related stuff, which tends to be a lot of VoIP via Vonage and Skype and TTY type stuff, but there's also standard definition Netflix streaming happening as my kids watch the occasional Sponge Bob or Backyardigans episode.
At night there is usually at least a standard definition video stream happening, plus VoIP, plus traffic from the XBox for game data.
I'm definitely running the DIR-655 hot with all this traffic now. And a bi-daily reboot because it's locked up is not uncommon any more. It's as well vented as can be, I just don't think it can keep up with the demands.
So how do I scale up to the next level? I don't mind spending some money since having consistent network is a requirement for my business. On my wish list is:
- More Gbit wired ports (there's a NAS in my near future and I'd wire more if I had more ports)
- The ability to put more machines in the DMZ (I'd hang my 360, PS3 and Vonage router in the DMZ if I could -- right now it's just the Vonage router)
- The ability to extend my wireless network (right now coverage is lousy on the top floor of my house and the signal doesn't exist in my back or front yard which means I can't work outside in the nice weather; something I'd like to be able to do)
- Good traffic shaping and traffic prioritization so I can balance Netflix streaming during the day with business traffic, and the different types of entertainment and communication streams after hours
Should I be looking for separate pieces (wired router, wireless bridge) to make this a more small-office grade network? Are their wireless components that will let me better extend my wireless network to the outside of my house? Without asking for shopping recommendations, I'd like to keep my budget in the
Source: (StackOverflow)
I’ve connected my working computer with another one using direct Ethernet cable. The other machine has no peripherals attached and I want to access it using RDP and SMB. The IP addresses are auto-configured, so it gets something in the range 169.254.x.x.
I can wait until Windows recognizes the other machine or scan IP addresses but both takes long and unpredictable amount of time. Is there any faster way to recognize the machine on the other end of direct Ethernet cable? I’ve thought about making a broadcast “Ethernet ping” and reverse ARP but cannot find any instructions for this technique.
Source: (StackOverflow)