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

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What is the difference between an Up MEP and a Down MEP for Ethernet OAM CFM?

I'm having trouble understanding the functional difference between an Up MEP and a Down MEP in CFM applications. Some sites say they are defined based on network direction, others seem to think they ...
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16 views

Unable to ping a computer with the same IP-range in another network through routers in the middle

I have two routers that are connected to each other through Ethernet. Their WiFi-interfaces are broadcasting two networks with same ESSID, IP-range and subnet-mask, using different channels. The ...
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0answers
16 views

Can't change interface duplex and speed on linux

I have eth0 interface with local ip. After reboot, interface have 10 speed and half duplex. After change with ethtool ethtool -s eth0 speed 100 duplex full autoneg off\on link is down, after link ...
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1answer
34 views

How do I increase the ring parameters for a NIC on a Linux server

I used the ethtool utility to increase the rx and tx values for the NIC on one of our servers. I ran the following command: ethtool -g eth0 Ring parameters for eth0: Pre-set maximums: RX: ...
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1answer
32 views

Any benefit and/or risk in enabling Jumbo Frames for the DAG replication network?

Exchange 2013 DAG, two nodes, a dedicated GBE network interface on each server for replication traffic, connected to a GBE switch, using a dedicated VLAN. Is there any benefit to Exchange replication ...
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88 views

Problems with Juniper Pinging Local System IP Addresses

I want to send a signal from "local system A" to an untrusted port on my SRX240(ge-0/0/0). I connected "local system A" to the SRX240 ge-0/0/0 port with an ethernet cable. To make sure the connection ...
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1answer
27 views

How is the Juniper Ping command working?

I connected a system to a Juniper srx240 with an Ethernet cord. I set the port where the Ethernet cord enters the Juniper from the other system to have IP address 222.22.4.1 and the other system has ...
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1answer
15 views

How to fix non-working ethernet under Linux, with RX permanently increasing?

I have a system with the latest Linux Mint. An ethernet cable which yields internet with no special action from me under Windows 8.1 is detected under Linux, but does not seem to work. Running ...
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1answer
36 views

Connect access switches to router or core switch

My workplace consists of 4 access unmanaged network switches from three different computer rooms connected to a router. The router contains three 100mbps ethernet ports and one Gigabit (GigE) port. ...
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1answer
44 views

Is it possible to tell whether I am connecting to fast or gigabit ethernet with CAT5e cable?

My NIC supports gigabit ethernet: $ ethtool eth0 Settings for eth0: Supported ports: [ MII ] Supported link modes: 10baseT/Half 10baseT/Full ...
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1answer
30 views

Does the IP -> Ethernet multicast address mapping ambiguity matter for IGMP snooping switches?

There are 2^28 possible IP multicast addresses, but only 2^23 possible Ethernet (MAC) multicast addresses (http://technet.microsoft.com/en-us/library/cc957928.aspx), which is why e.g. 224.1.1.1 gets ...
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49 views

OpenVPN cannot connect to local machine that has two NIC cards

This is my first time EVER posting to these forums. Most of the time when I have an issue I can usually solve them by searching forums/Google. But this one issue has me stumped! My company just ...
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1answer
45 views

Two LAN cables when using Remote Access Card?

I recently bought a HP MicroServer N54L and a HP Remote Access Card. Connecting to the server over a KVM viewer for BIOS setup etc. works fine, but when it comes to installing Ubuntu 14.04. the ...
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0answers
62 views

Can't seem to see local network on Wine

I'm trying to use Wine on Ubuntu to use a proprietary Windows program that looks for a proprietary device on the local network. I don't know where it's looking, which protocol, port or IP address it's ...
2
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1answer
233 views

Is there a standard managed switch configuration protocol?

is there a vendor-independend managed switch configuration protocol e.g. for creating VLANs that can be run over TCP or serial port?
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1answer
54 views

What is the most proper way of wiring RJ45 for Cat6/LAN?

I currently know of three different wiring patterns for RJ45: T568A, T568B, and USOC. Simply put: Which is the best method for creating a Cat6 cable? From my research, it seems like I should use ...
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1answer
100 views

ethernet switch makes network down [closed]

I have a D-Link 8-port Ethernet switch which was perfectly working. Since 2 days ago it makes the entire network down. The problem is when I disconnect the cables it runs again and after I connect ...
2
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1answer
509 views

e1000e Reset adapter unexpectedly / Detected Hardware Unit Hang

I have a Dell 1U Server with Intel(R) Xeon(R) CPU L5420 @ 2.50GHz, 8 cores running Ubuntu Server Kernel Version 3.13.0-32-generic on x86_64. It has dual 1000baseT networking cards. I have it set up to ...
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1answer
20 views

Why am I seeing prefixed/duplicated packets coming from a comcast device?

I'm looking at traffic my CPE from Comcast in Wireshark, and for every packet, there is an additional packet that is the exact same, except for 4 additional bytes at the beginning of the frame ...
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2answers
290 views

What does 'Si' mean with respect to network switches?

I am seeing references to Multilayer Switches with Si as in the network symbol below. What does the 'with Si' qualifier mean?
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0answers
71 views

zeroshell unsupported onboard Intel Ethernet I217-V and I210

I recently installed zeroshell 3.0.0 on a machine with a supermicro motherboard that has 2 onboard ethernet cards. It seems that this version of ZS does not support both of ethernet. I've read from ...
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1answer
70 views

Suddenly unable to obain IP address but eth0 port blinking rapidly

After a server restart, the server is unable to obtain an IP address through a wired ethernet interface, neither automatically nor manually. However the green light on the back of the machine where ...
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3answers
452 views

Gigabit uplink versus regular switch port

I have a 10/100/1000 24-port + 2 mini-GBIC ports switch which I have to link to other switches. Unfortunately, on the other switch all the mini-GBIC slots are taken up, so all I can do is link them ...
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1answer
45 views

Ethernet switch signal quality

Is there a (significant) signal quality difference between ethernet switches? n other words: A 1000base-t, do some switches allow longer cable runs than other switches?
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82 views

How can I change metric of public network in route table

In my windows 8.1 ENT [64 bit] machine I have 3 network adapters. Ethernet 1 is connected to public network and other 2 ethernet adaptors are connected to different internal networks. The problem is ...
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2answers
404 views

Should Carrier Ethernet traffic be encrypted?

I'm looking for a best practice answer. We have a 100Mb point to point Carrier Ethernet circuit between a corporate office and an offsite data center. Basically we have SQL traffic replicating to ...
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38 views

AR8151 eth0 heavy trouble

First I had really bad issue with network speed. There I got this good article: http://mindmapapp.blogspot.com/2012/01/use-atheros-ar8151-ethernet-card-on.html But now I have really crazy things ...
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1answer
21 views

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
114 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
66 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 ...
2
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1answer
180 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 ...
6
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1answer
374 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
787 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
75 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
154 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
147 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
34 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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48 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
59 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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145 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
160 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 ...
3
votes
1answer
70 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. ...
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0answers
1k 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
418 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
86 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
407 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
95 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
215 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 ...
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1answer
253 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
52 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 ...