Networking :: Why Ethernet Is Used Only In Local Area Network?
Dec 25, 2010
One question that weight a lot of points was about ethernet... the professor asked why ethernet is used only in local area network? resuming i wrote that ethernet is used only in LAN because it is shared and so for big network there could be a lot problem in using the shared channel.. for istance using protocol such as CSMA/CD, if a big network has a lot of hosts, they could wait a long time before sending...is it right or am I wrong?
I'm working with a Ubuntu 10.04 LTS system with two network interfaces (both Ethernet). I wish to setup this system such that it is simultaneously connected to my local and an OpenVPN network and able direct traffic between the connections depending on what program is sending the traffic. The problem: Under my current OpenVPN configuration all network traffic is directed to the VPN.
In practice, I would like OpenVPN to operate out of one of my two network interfaces and leave the other interface connected to the local network. Then by default all network traffic should be directed to my local network unless I specify (on a per program bases) that certain traffic should go though the VPN. These two network connections can (should) stay completely independent of each other and do not need to talk to each other.
I have a computer, the one I am on now, with Ubuntu 10.10, it should be completely updated... and I can network with other computers, I can access Windows XP and 7 shared locations on other computers, and I can also get Ubuntu on other computers to access this computer's shared files.What I can't do, however, is share my hardrives that are on this computer, I have tried sharing them in /media/ and etc, but it is not working, apparently you have to mount them in some mystical way.
Another problem is getting Windows machines to access Ubuntu computers on the network - which I believe is a Windows problem, so I can figure that out some other time, but importantly, I want to be able to share my hardrives over the network.
If someone can give me some instructions to mounting and sharing hardrives(internal), and even my DVD-Drives, and portable USB devices, would also be fantastic - since, in Windows you can just right click, "share", and it's done.. It is a very useful thing to have, and I don't want to use Windows on this computer anymore, but I have no choice, really, if I can't share my storage to the other computers.
I just installed open Suse 11.3, and I cannot SSH my school. Upon further investigation I could not even ping any machines outside my local area network. Ironically I could nmap machines outside my local area network.
At home I have two computers running linux connected to the same router. I would like to be able to connect them so that I can move files between them and execute simple commands. What is the most simple way to access a prompt on the other computer or to mount a partition currently used by the other computer?Using the www it is possible to connect two computers using ssh, but it should be easier to do this over the LAN, right? I have been googling a lot but not found anything.
I am new to networking and trying to setup my own local area network using virtual box machines. I have installed BIND 9.7.3 using yum in Fedora (dns server) and created all necessary .conf and zone fil es. I am successfully able to resolve domain names on this host machine (dns server). for example dig @dns.domain.lan client1.domain.lan correctly resolves domain name.
i have successfully done the setup of postfix and dovecot on this link [URL]I run Cent OS on top of window 7 via VM Player,i want to access mailbox from windows 7 using email client like Thunderbird and Outlook. What setting i need to do in my mail server ?
I'd like a way to see all of the devices on my local network and what their local IP address is. I recall that I used wireshark to troubleshoot a similar problem a while back, but it doesn't seem to have a way to see all of the devices- only the traffic. (I'd like to do this without having to physically interface with my router if possible, and I am in an encrypted network if that matters)
I have installed a web server on my local network. Everything is well configured and web pages are shown correctly from Internet (outside the local network) using the domain or the public IP.The issue is if I try to see that web pages (using the domain or the public IP) from inside the local network. In that case the router config page (192.168.1.1) is shown instead of the web pages.From inside the local network I'm only able to see the web pages using the internal IP address (192.168.1.XX).
I've got an Ubuntu server hosting our websites and other various things here in our own home. We recently switched to a router that doesn't support loopback (abomination), so I've set up hosts files on our computers so we can access our own sites when on our home LAN.
However, we often take our laptops as we travel about, and I'm guessing due to the hosts files when we try to access our sites, it'll look on whatever local network we're connected to for our server, which won't work, obviously.
Is there a way to set up something like a hosts file that'll only try to look up the local IP of the server when we're on a specific network (our home one), or have one that tries to look for the local IP first, then proceeds to try and resolve the domain name and use the external IP if the local IP doesn't work?
On about 90% of bootups I find that network manager has disappeared from the notification area to be replaced by a random duplicate of one of the other icons (at random). If I remove the notification area and add it again all is fine.
am new to ubuntu, have some issues with connecting to wireless. I have downloaded my wireless drivers and installed, I can see that my wireless is on from the indicatior, but I cant connect to any wireless access point because I cant locate network manager on the notification area. Am using Dell inspiron 1501.The second issue I have is connecting as root. after I installed ubuntu, it created a user for me which I specified during installation, but most things am doing requires root privilleges. I cant connect as root because I dont know root password, I have tried changing the password but it doesn't go. Pls guys help me sort out these issues.
im just getting the hang of ubuntu 9.10, and then all of a sudden 10.04 comes over and screws everything up with the upgrade. i did the upgrade, and now the network manager wont show up in notification areas. any clue as to why? help is greatly appreciated. also, my machine does register that the drivers for wireless card is installed, and when i run lshw -c net command with sudo priveleges, it says it can detect networks, so im confused as hell.
I have a system running a very basic LTS install (10.04). Ubuntu has been setup with very little additional packages. No GUI. Once it's booted to a prompt for the first time I add the following packages,
cups cupsys ssh pi memtester nfs-common aptitude safe-upgrade
At this time I don't have additional information on exactly what packages are installed. I did not perform the installs myself. I will update this thread when I get more details from my IT counterpart on how the system was setup.
This is used for a headless(no monitor, no keyboard) system running some custom applications.
Here are two problems.
1. If I plug into an ethernet network after I boot, the network never connects. I need to reboot with the network connected in order to get an IP. What is the service to "auto connect" to a network?
2. I have a network printer configured on lpd called myprinter. If I am connected to the network when I boot, I can print to this printer just fine using:
However, If I boot disconnected from the network and print to myprinter, the jobs obviously cannot print. They get spooled. Using 'lpstat -t' I can see that the spooled print jobs are assigned a job number and that myprinter is trying to connect. I shutdown, reconnect my ethernet network and boot up. All my printer configuration is blown away.
/etc/cups/printers.conf has been wiped out to look like this:
My 'good' printer configuration is copied to printers.conf.O
To recover from this, I need to stop cups, copy printers.conf.O to printers.conf, restart cups, and re-setup my network printer.
So, What causes my printers to get wiped out? I've repeated this on 4 systems with the same setup.
I have two networks. One of them is wired, the other is wireless. The wired has an internet connection and a few other computers connected to it. The wireless network has a few hosts connected to it too, but it has no internet connection. What I've been trying, fruitlessly, to do, is make all connections that are bound to the internet, or my wired network, be routed that way, and all the connections to the hosts of the wireless network go that way.
Here's the setup..
192.168.1.0/24 Gateway = 192.168.1.1
Route internet through here
192.168.2.0/24 Gateway = 192.168.2.1
If my computer sends a packet to the internet, it should be routed through 192.168.1.1 If I send a packet to one of the local hosts of the wireless network, it should be routed through 192.168.2.1. Here's the routing table I've set up(This is one of many configurations I've tried)
$ ip route show 192.168.2.1 dev wlan0 scope link 192.168.2.0/24 via 192.168.2.1 dev wlan0 src 192.168.2.4
With this, and everything else, I get destination host unreachable when pinging. The strange thing is that, if I unplug my eth cable, reboot and connect to the wireless network, everything is fine and I can access the router and the others. I'm trying to improve my networking skills, as I've had this of setting up a small linux box as a router for quite some time, for the fun of it, but I need to get routing under control before I go ruin my network.
Hi. I have Ubuntu 10.04, nm-applet is running in the background, my battery icon and sound icon are showing but my network icon has been missing for the past 2 days. It was working fine before but now it's not. How can I fix this issue if I don't have an ethernet cord? Is there a way to roll back the recent updates or do I need to reinstall my network manager?
I've tried restarting the system and I've tried killing nm-applet and reloading it using Alt F2. I get some Debug error.
When I try to run nm-applet --sm-disable
It says an instance is already running and then gives me a warning.
I tried removing "iface eth0 inet dhcp" from /etc/network/interfaces and then tried restarting by "sudo /etc/initi.d/networking restart"
What can I do to connect to the internet? I have a flash stick if its possible to download a .deb package on this mac and transfer it over to my other laptop to fix the problem. If its possible.
My hardware has two interfaces: a) ethernet - eth0 b) WirelessLAN - eth1.After power on, eth1 gets associated to WirelessLAN access point.
The ethernet interface of Hadrware and test PC is directly connected to Wireless LAN access point through ethernet cable. Hardware is associated to Wireless LAN access point through eth1 interface.Now, when ethernet cable is connected to hardware, I can ping 192.168.254.254 from test PC.When I removed ethernet cable from hardware, I cannot ping 192.168.254.253 from test PC.I think access point should forward the incoming packet from test pc to hardware's eth1 interface wirelessely. Where am I wrong? Is it related to Kernel's routing table? If yes, how to detect removal of ethernet cable from hardware and change routing table dynmically?
Ok, so I've gotten tired of my router, and I've decided to make my own using IPFire as the OS. Right now I'm looking for ethernet cards that I can use for the green network, but I don't know if I can use 2 for the same network. I'm trying to get 4 ports at 1000 Mbs, and the only thing I've been able to find so far that's within my price range is a card from startech that has 2 ports, but would I be able to use 2 for the green network?
I currently have a computer sitting underneath a router/switch on a Local Area Network that I want to connect to the Internet using a 3G USB dongle modem. If I am connected to the ethernet and then enable the modem connection, only the ethernet LAN side works. If I enable the modem and then enable a (disabled) ethernet connection, only the ethernet LAN side works. If I keep the ethernet disabled and connect using the modem, I can get out onto the Internet, but obviously not the LAN. I need to be able to do both.
Problem:I got a new Acer Aspire 8935G notebook, installed Ubuntu 9.10 on it and everything is fine, except the fact, that it wont detect any network interfaces (or how to call it So there are no ethernet or wlan connections available in the network-manager..
lspci gives me following lines: joe@IGNAZ ~ $ lspci 00:00.0 Host bridge: Intel Corporation Mobile 4 Series Chipset Memory Controller Hub (rev
If i want to use SSH to log on to my home computer, which is connected to the router, how do I go about connecting to it?If I get my external IP of the computer at home, it will show me the external IP of the router correct? Then I need to forward the router's external IP to my computer at home. But then, how do I connect using ssh? or do I need to consider my local IP of the computer at the router's network?
how to resolve an ip with a port in linux?, how to include this on the dns. So the user don't have to remember the ip address and the port. like the user will only type http://scanfiles then it will resolve the corresponding ip. is it possible?
Let me start off by saying everything WAS working...I have a lab environment comprised of two subnets (.1.128/25 and .2.0/25). On the .1, I have 3 Solaris 8 servers running NIS, NFS, databases, DNS, various services, etc... the network was setup on VLAN'd Layer 3 switches with the VLAN interface addresses acting as default gateways (dgw) for the two networks (on a single switch). The switch dgw was a router for outside connectivity. The servers are running ODCS OpenSSH.I was having problems with the VLANs, so I reconfigured the network so that each subnet had it's own switch as a dgw, and they route through a point-to-point static route setup as 192.168.0.1&2 on a separate VLAN between the two gateway switches.Here's where the problems start:First, ALL the services (NIS,NFS,databases,DNS,etc) are STILL WORKING. I can ping all the addresses. Traceroutes show the proper path thru the point-to-point, etc. There are NO firewalls setup, hardware or software, network or host-based... no iptables running, etc.
The three servers are on the .1 network. I can ssh to them from hosts on the .2 network no problem. However, I cannot complete an ssh login to them from any host on the .1 network. I get a password prompt, enter the pwd, and then it hangs until I receive a "Connection timed out" error message several minutes later. The next time I log in however, it shows "Last successful login" from the failed attempt.While the connection is hung, netstat on the server shows "ESTABLISHED" to the client on the proper port. nother odd indication is that I CAN sftp to the servers from hosts on the .1 network.
I'm a new user of Ubuntu, so i'm not that familiar with this OS. My wireless network is detected but when I'm entering my 128 bits WEP key, it doesn't connect at all. I have no clue where to start troubleshooting.
Here's some of my specs if that's of any help: Computer is a Sony Vaio laptop model VGN-SZ370P My wireless card is from Intel Corporation 82801G (ICH7 Family) USB UHCI Controller
The ethernet cable connection used to work before, but I fooled around with some commands and now seems to be disabled...
I installled Ubuntu 10.4.1 on a brand new computer with a Realtek RTL8111/8168B PCI Express Gigabit Ethernet controller on a Foxconn G41MXE motherboard. and I have been unable to connect to wireless network. I have gone through the wireless trouble shooting guide to no avail. When i "check for device recognition" i get the following (note the is no CLAIMED UNCLAIMED ENABLED OR DISABLED)
Running Ubuntu 9.10. In the Remote Desktop config dialog I get: "Your desktop is only reachable over the local network. Others can access your computer using the address 127.0.0.1 or tabatha.local." I understand this means only the loopback ip address is available. All my other machines show their true local ip address (e.g., 192.168.1.104) in this dialog. Thus I cannot log on to this desktop from other machines.
When I try to do a remote logon from another Ubuntu 9.10 box (or from an XP box using a VNC viewer), I get: "Connection to 192.168.1.102 has been closed." What steps are needed to make this machine show its actual ip address? All file sharing between the various machines is working properly and all windows shares back and forth between XP and 'nix, and among the the vaious XP boxes and linux boxes are available as designed.