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

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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
440 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 ...
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113 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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25k 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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3k 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 ...
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154 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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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
540 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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78 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
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683 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 ...
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1answer
216 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
235 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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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 ...
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2answers
592 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 ...
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1answer
962 views

Is it ok to use cat5e patches/jacks on cat6a cable for 10Gb

I understand that "technically" you are supposed to use cat6 cable jacks as well as cat6 patch panels. In practice I've seen cat6a plugged into cat5e patch panels, although I've never seen cat5e ...
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504 views

patch panels… or directly to the switch?

does it make a difference in terms of signal quality if I connect the Ethernet cabling: from the wall-plugs to the patch-panel and from the patch-panel to the switch with a cord. as opposed to: ...
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1answer
432 views

How can I stress an Ethernet managed Switch?

for testing purposes I need to stress an 8-port managed ethernet switch. Essentially, I want to simulate a scenario in which two hosts on the switch are exchanging data and the other hosts connected ...
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1answer
94 views

Ethernet Frames and CSMA/CD [closed]

I'm learning about Ethernet and I'm wondering if with several stations within the same Ethernet collision domain like pictured below, is it possible that a frame sent by station A is fully received by ...
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1answer
351 views

Maximum throughput on switch with different link speeds

While doing some benchmarking on a network app I discovered strange behavior that involves 100MBit and 1GBit ethernet clients connected through a switch (at-gs900/8e). I have one server (Gbit) and ...
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2answers
317 views

TIA 568A vs. B Wiring for Long Ethernet Run

I have a long Ethernet run (about 280 ft/85 m) that goes through a conduit between two buildings. On each end, I have an APC Ethernet surge protector that is grounded to the main ground for each ...
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1answer
609 views

Linux network interface broadcast statistics

I am looking for a way to see the number of Ethernet broadcast frames transmit/received by the network interfaces. I am familiar with many Linux commands,procs and options to get interface statistics ...
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3answers
261 views

CentOS Network Interface Priorization

I have a CentOS server with 2 network interfaces with configurations: eth0: DEVICE=eth0 BOOTPROTO=none BROADCAST=10.0.0.255 HWADDR=xx: IPADDR=10.0.0.2 NETMASK=255.255.255.0 NETWORK=10.0.0.0 ...
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402 views

Is it possible to use WPA2 over ethernet?

Like, as in requesting a "password" to connect, just wondering. Also, are any of these (VPN, public key auth?) methods either possible or implemented?
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2k views

OpenVPN to host tap device having very large MTU

Question What is the minimum set of server and client configuration directives that I need in order to satisfy the following conditions? Virtual layer 2 ethernet network that will not be bridged ...
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Can Wireshark capture an entire Ethernet frame including preamble, CRC and Interframe spacing?

I am examining an Ethernet frame in Wireshark. According to the "Ethernet frame" Wikipedia article and accompanying diagrams, "A frame starts with a 7-octet preamble and 1-octet start frame delimiter ...
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1answer
1k views

10GbE be2net low pktgen performance

I am testing the network performance of two workstations, each having 2.4GHz Xeon quad core processors and NC550SFP PCIe Dual Port 10GbE Server Adapters, linked back to back. I've checked the ...
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410 views

Source and Destination Packets on Wireshark Relative or Absolute?

New in Packet Analysis. Sniffing on the Ethernet device of my computer. Does the Source and Destination columns on Wireshark tell the source and destination from where the packet was originated and ...
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2answers
171 views

Switch between network configurations via command line in fedora 17

I have two different setups I use on my work laptop; one enables synergy over an ethernet ssh tunnel with my work computer on the local network, and the other opens an HTTP tunnel to my work computer ...
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171 views

bonding - balance-tlb and a mysterious ethernet packet with lots of 00:00:00

Whilst attempting to get bonding working with mode=5 (balance-tlb) it seems that the driver sends an ethernet packet with length 0x0060 and the data, payload is all zeros. I can't work out where this ...
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2answers
453 views

Tunnel Ethernet Packets over SSH

I have two machines. My laptop and a machine in the local intranet. This machine has next to the network device (for the intranet) a second network card. I want to send raw ethernet frames out of this ...
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1answer
272 views

Missing Ethernet preamble [closed]

I am helping my colleague debug his problem. Basically, there are two 10M devices, and only one of which we have control over (the other being a "black box"). Analyzing the Ethernet hardware signals ...
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2answers
5k views

Is the 64-byte minimal Ethernet packet rule respected in practice?

A quick WireShark scan of my network interface reveals a bunch of Ethernet packets which are less than 64 bytes in length. I know that WireShark strips off the trailing 4 byte CRC, but I still see ...
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362 views

Enabling Ethernet X3530 M4

I have IBM X3530 M4, and it appears to have 4 ethernet ports, but under Ubuntu just 2 ethernet ports are enabled. How can I enable the other two ethernet ports?
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320 views

Extending a PaGP EtherChannel run beyond the maximum ethernet length [closed]

I have an office downstairs which requires approximately 500 feet of cat-5 to reach. We have a basic L2 switch in a closet at the halfway point which acts as a signal booster, and allows us to give ...
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2answers
519 views

How do fiber Ethernet transmitters set their power output?

I've noticed that fiber-optic SFP modules from Cisco and the like often specify a range of power outputs, such as -3 to -9 dBm. What determines the actual power output we should expect to see from ...
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1answer
220 views

Bond0 Failover when link light stays up: High Availability Network

Configuration: Two switches, each with a separate internet route Centos servers with eth0 and eth1 bonded as an active-backup on bond0, eth0 in on switch and eth1 in the other /etc/modprobe.conf ...
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3answers
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Effect of reversing a pair, in cat5 cabling (e.g. swapping stripe and solid)

Is there any practical effect of reversing solid and stripe, when wiring cat5 cables? But if I've got a cable where each pair is a pair but one end is flipped, will this make any practical difference ...
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57 views

Calculation units in EtherType frame field [closed]

The EterType ethernet frame field value is represent a payload field length in bits or bytes?
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24 views

Interface eth0 not reacheble outside LAN

First of all, sorry for my bad english. I configured my two interfaces, eth0 and eth1! Bove have the LAN IP 192.168.0.10 and 192.168.0.11.... everything ok. The problem is, eth0 is reacheble from ...
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2answers
541 views

Need to “extend” wireless signal to conference room

We have a network set up using an ASUS RT-N66U for our office with the following configuration: Private SSID (one for 2.4 GHz and 5 GHz) Guest SSID (one for 2.4 GHz and 5 GHz) Unfortunately, we've ...
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132 views

obtain the MAC Address/interface name from GUI on FreeBSD?

Is there any way I can obtain the MAC Address/interface name from GUI on FreeBSD? Are there any system calls to do that? I was searching everywhere but couldn't find any information. Can you please ...
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70 views

How to build a L2 Ethernet with 1000 comupters?

We don't really have 1000 computers. I'm asking this question just because my brain is blocked here. If I put a number of, say 1000, computer on a L2 Ethernet. Since most of L2 switch has only maybe ...
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1answer
104 views

Multiple ethernet interface on one ethernet card

First I must say that I am new in linux and maybe I will ask trivial question. My job is to create 8 ethernet interface to be visible in kernel, but all of them should send and receive data through ...
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487 views

Why do metal fasteners (e.g., staples) around ethernet cables impair network performance? [closed]

At one point I was living in a 6 bedroom home that had cat 6 ethernet wired to each bedroom. The internet connection to the bedrooms furthest from the cable modem had terrible performance, though I ...
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1answer
828 views

troubleshoot Ethernet (layer 2) without layer 3

I am troubleshooting a LAN and the problem is to make sure each host can reach each other at layer 3. Each host is configured to the same subnet, but some hosts cannot reach other at layer 3 (e.g. ...
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1answer
41 views

Use or not to use multiple ips on the same network card?

I got a Dell r620 that cames with 4 network interfaces. If I have for example 4 ips, and want to assigne them to the server. What would be better, in terms of performance. Add all the 4 ips to the ...
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1answer
594 views

command for MAC broadcast

I am looking for a command to discover all hosts on the same LAN segment from a host with unassigned IP, default gateway, and subnet. I know there's ping 255.255.255.255 but that operates at layer 3 ...
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2answers
338 views

How can I make a secondary NIC port “eth0”?

I am using CentOS 5.9. One of my servers recently had a malfunctioning NIC port. The software running on the server was hard-coded to use eth0. The other physical NIC ports were fine and unused. The ...
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1answer
239 views

Supress FreeBSD “link down: cable prοblem?” messages

I have a FreeBSD lab machine that is regularly connected and disconnected from the network, sometimes to borrow the port temporarily for another machine and other times to test the ability of certain ...
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54 views

How to determine remote link speed?

I'm on a non-manageable switched 1 GbE network with mixed 100 MbE and 1 GbE hosts. Is it possible to tell if a certain host has a certain link speed without looking at the status LEDs of the switch ...