Ethernet is the most common set of standards for wired connections in local area networks.

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Use local Internet connection

I have a network split into through two ethernet segments through a virtual VPN hub. In the figure, blue is the part of the network that I control. My problem is due to the orange subnetwork, that ...
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1answer
172 views

Network latency caused by incorrect cable?

Our team recently setup a new network and now we are experiencing network latency issues. the flow of traffic is as such: modem -> router -> packet shaper -> cisco3750 switch from router to packet ...
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1answer
73 views

Splitting Ethernet cable [closed]

I am looking for the best way to network my small business. I have an office where my router/modem are located, and then 2 more computers in another room. I can route Ethernet to this room with about ...
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1answer
852 views

Full MTU not utilized with jumbo frames enabled

I've been testing to see if I can get any benefit from enabling jumbo frames. I've set up two identical Dell R210 servers with Xeon quad core E3122 CPUs, 8G of RAM and Broadcom NetXtreme II BCM5716 ...
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1answer
615 views

Is it possible to detect rx+ rx- tx+ tx- wires with multimeter?

Is it possible to detect rx+ rx- tx+ tx- wires of an ethernet cable having only a part of cable with multimeter or somehow else? I mean the situation when you have just one side of the ethernet ...
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2answers
3k views

Connect two networks to a single server using its two ethernet ports

I have two separated local networks (two routers, each is connected to its ISP for the internet connection) and a server with two ethernet ports. The server is running a local website service which I ...
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1answer
232 views

Is that MAC-48 address valid: “01:23:4:56:78:9A” [closed]

Wikipedia states about MAC-48 string format: The standard (IEEE 802) format for printing MAC-48 addresses in human-friendly form is six groups of two hexadecimal digits, separated by hyphens ...
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2answers
250 views

Calculating required uplink capacity of network switch [duplicate]

Is there any common method (usable in practice) for estimating the uplink capacity of switch based on known number of users connected to this switch and the maximum internet speed they are allowed. ...
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4answers
226 views

Which way up does an ethernet port go? [closed]

I've scoured the internet, but nobody seems to be able to decide whether RJ45 sockets should go with the release catch facing up or down. For instance, Netgear has their ports this way: But Cisco ...
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1answer
57 views

Broadcast stop via loopback kills bandwidth

Why does creating a broadcast storm by directly connecting two ports on a switch cause the bandwidth to all the other ports to cease?
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99 views

ZyXel ES-2024 - Mirrored port showing duplicated traffic

I have a ZyXel ES-2024 PWD switch. I would like a computer plugged into port 26 to see all traffic that passes through port 2, both inbound and outbound. I have configured port mirroring for the ...
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2answers
71 views

Is it possible to produce an unfair ethernet NIC?

The ethernet MAC protocol is based on CSMA/CD, which defines an algorithm for fair collision handling: If the NIC detects a collision, it sends a jam signal and enters binary exponential backoff: ...
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217 views

Ethernet link not detected under Linux 3.6.9, but is ok in 2.6.39

I have a custom Linux appliance with a 100M ethernet port. Under the 2.6.39 kernel, networking was never an issue. Autonegotiation worked just fine, as did network transfers. Now, with the newer ...
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1answer
576 views

Restrict network connection to virtual machine alone-VMWare

Is there a way to restrict a Ethernet/Wifi Connection to the virtual machine alone and not to the host operating system? I am using VMWare workstation on windows with centOS and Ubuntu as my guest OS ...
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2answers
105 views

Is a DCB switch required for a FCoE setup?

I'm looking to play around with a test Fibre Channel over Ethernet (FCoE) deployment between 2 Xen servers and 1 storage server. Eventually I plan to replace our ageing NFS shared storage solution. ...
2
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1answer
3k views

eth0 NIC Link is Down repeating message in kernel log

I've noticed since few days ago that same repeating kind of messages occurs and I positively can say that nothing was intentionally changed (installed/uninstalled) in that period. here's sample of ...
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3answers
883 views

Windows Server TCP sockets random disconnect: how to reproduce?

We rented 10 Windows servers from a large provider in Europe. They all work as expected. One server suddenly crashed and customer care found that both disks were broken. They replaced disks and also ...
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1answer
184 views

Networking service not responding [closed]

Networking is going down on some of our machines. This is happening very randomly. Restarting networking is fixing the issue. I found the following in the kernel logs: Mar 19 18:19:05 <host> ...
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2answers
782 views

Connecting VoIP Phones to a Laptop

I'm trying to connect two VoIP phones to a laptop using the internal ethernet adapter and a usb-to-ethernet adapter. My configurations are as follows: Laptop eth0 - 121.1.2.1/24 Gateway - 121.1.2.4 ...
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2answers
136 views

Different speed on Internet connection by switching NICs. Can someone make sense of this?

I solved my Internet speed problem, but I'm still puzzled. I can't understand what happened. My scenario: a small intranet is connected to Internet through a Linux gateway that connects to a Cable ...
2
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1answer
454 views

Automatically acquire IPV6 address in CentOS 6

The network has fixed IPv4 address, and automatic acquired IPv6 address. Does anyone have an idea how to setup? Thanks a lot! I didn't use NetworkManager. The following is my setting, but it does not ...
4
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1answer
637 views

Why 10GbE card cannot negotiate 10Gbit with Windows 2012R2?

The Problem I've got four identical blade servers. I've got Windows Server 2012 R2 on one blade and Xen on all the others. On the Windows-hosted server (only) the 10GbE NICs cannot negotiate ...
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1answer
84 views

Strategy for forcing cam table updates from custom hardware

I have a system that consists of a control PC, two layers of switches, and 50 custom devices. The PC continuously streams a total of 5.8MB/sec (6000 ethernet frames/sec) to the devices. I have ...
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1answer
1k views

VirtualBox VM network hangs due to ethernet “Reset adapter” [closed]

I have a VM which I've created on a host using the following settings: http://pastebin.com/raw.php?i=sevF5V7Z It has been up and running smoothly for months but recently the VM lost connection with ...
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0answers
71 views

ethernet RX/TX drops to zero, is it normal? No problems at all discovered

I am using Debian Wheezy 7.1 [3.2.0-4-amd64 #1 SMP Debian 3.2.46-1+deb7u1 x86_64 GNU/Linux] and when monitoring eth0 via Slurm or built-in System monitor I am getting: Current RX Speed: 1883.11 KB/s ...
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2answers
73 views

Network Switch Terminology (MAC address table) [closed]

When a switch has the ability to learn what MAC addresses each of its ports serves, then uses that to determine which port to send ethernet packets out, what is that feature called? Also, does every ...
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4answers
120 views

Same static IP addresses to single static IP address communication [closed]

I have a server with 4 modules, and one Ethernet Port and an internal hub to assign these modules to, configured as below. Module 1: 192.168.10.1 Module 2: 192.168.10.2 Module 3: 192.168.10.3 ...
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2answers
724 views

Point to Point Connection Between Two Hosts

I am trying to set up a point to point connection between two Linux host machines. I've connected both of them with crossover cable, but they can't ping each other. Here are the configurations for ...
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1answer
615 views

Ethernet Bridging With USB-to-Ethernet Adapter

I have a USB-to-ETHERNET adapter (CP-USB-RJ45M) with which I am trying to create an ethernet bridge in CentOS Linux for ip-forwarding within a private LAN test network. I modified my /etc/rc.local ...
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2answers
654 views

How to detect ethernet uplink speed on CentOS 6 OpenVZ VPS

I recently purchased a VPS which was advertised as a 100Mbps uplink but the promotion promised a free upgrade to a 1Gbps uplink. I'm trying to find out if I received the upgrade with various methods ...
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1answer
79 views

Why do network cards seem to work fine without firmware in Linux?

I have computers with Intel and Realtek Ethernet cards, and I keep forgetting to install the linux-firmware packages when I put Debian on them. I can see messages in syslog telling me that the ...
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0answers
190 views

How can i detect and diagnose local network problems on a multi-server environment?

I'm a software engineer who trying to detect (and solve if possible) weird local networking problems since 2 weeks on multi-server hosting environment. We bought 3 dedicated boxes with 32GB ram 8 ...
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62 views

MSTP with looped port

I have a configuration with two switches connected via a single Ethernet port. A second port of the first switch is looped back (Tx connected to Rx). They have 10 MSTI configured on VLAN from 100 to ...
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1answer
163 views

Ethernet is taking very long time to recover after switching loop

Problem generation is very simple like jamming a network without STP ;-) Ok, so steps of creating my problem is given as follows: Ping Device A from Device B. Reply is coming. Generate a network ...
0
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1answer
56 views

Would faulty wiring let you access the internet but fail to let you find a domain controller on the LAN?

I have been having a random issue regarding joining a domain at my workplace. II am a programmer, not a network tech, so I struggle with these issues and would like my suspicion confirmed In this ...
2
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1answer
1k views

Airport Extreme mesh over Ethernet?

I have purchased three Airport Extreme routers. I have a cable modem in one room that currently feeds into our primary router (which I want to replace with an Extreme), which feeds into a switch, ...
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1answer
45 views

USB Device With Embedded Fileserver

I'm attempting to access logs from a proprietary hardware box with no reasonable hope of modifying the software. There is a process on the device to dump log files to a flash drive on the USB port ...
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1answer
410 views

Viability of Mac OS X 10.9 Time Machine Server in office environment

Currently we have about 20 Mac OS 10.9 MacBook Pros (almost all with SSDs) backing up to individual USB drives. I'd like to consolidate these to one drobo thunderbolt drive array attached to a Mac ...
0
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1answer
97 views

Test ethernet port for data loss

We are trying to test the ethernet phy on our linux box for data loss. As of now we just establish a tftp connection to a server to upload and download a file. Whenever a mismatch occurs, it is ...
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5answers
20k views

ARP broadcast flooding network and high cpu usage

Hoping someone here might have some insight to the issue we are facing. Currently we have Cisco TAC looking at the case but they are struggling to find the root cause. Although the title mentions ARP ...
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1answer
2k views

“short” when testing an ethernet cable which is not connected to anything

There is a (~80m) Cat5e cable that stopped working a few days ago. I tested it with two different cable testers, and with both of them the result was: "short". Usually I get this result if there is a ...
0
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1answer
145 views

Unable to set initcwnd on a Hetzner server

We just ordered a bunch of Hetzner EX40SSD servers with the minimal Debian install image that they provide and everything is just fine except that looking at tcpdumps for fine tuning the network from ...
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5answers
3k views

A “splitter” is plugged into a patch panel… how does this still work?

I found a patch panel that splits off ethernet into multiple hosts as shown below. Can anyone explain how this might work?
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2answers
509 views

Ethernet port not detected

I just added additional 1gb port to my existing 4gbs on my server. All 4 are placed on a NET CARD PCIE 1GB E1G44HTBLK 904223 INTEL and the additional one is connected to motherboard(S5520SC) ...
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1answer
77 views

Ethernet interface drivers (e1000 and NE2000)

What's the difference between e1000 NIC driver and NE2000 NIC driver?? I have tried to find out the answer on google but not been able to completely understand the difference
0
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1answer
599 views

PS6000 showing packet errors but no errors appear on the switch

We have a loaned PS6000E SAN that we are using to relocate our iSCSI LUNs off our current PS4000E SAN to upgrade it from Seagate Moose drives under a proactive replacement plan by Dell. We've ...
2
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1answer
176 views

How does a NIC send a hardware interrupt? [closed]

Some context. A few weeks ago, a NIC was replaced on a box without much troubleshooting to find a clear resolution to the problem. A senior administrator got into a small tiff with an entry-level ...
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1answer
198 views

PPP or Ethernet for fiber-optic link?

Since I have been doing a lot of IP camera jobs lately, it was only a matter of time that something really long-distance, more than can be covered with cat5e/cat6 cable, would come up. My current ...
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1answer
34 views

Strange issue on netadapter lantronix matchport bgpro

I'm connected to a switch on a LAN, i've tested my matchport on others network and i've not accused this problem. On this istead i seen a lot of UP and DOWN of eht0 on startup. Someone know something ...
13
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2answers
518 views

Ethernet port plastic plug blocking port access on server

I have Dell Poweredge server with plastic blockers inside their ethernet ports. My problem is that I don't know how to take it out. You can see photo of the plug here: I tried to pull them out, or ...