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

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Assign more than one IP Address to the same MAC Address on Linux ISC-DHCP Server

I have the following question: One Linux DHCP server in pool mode, because of the step of fabrication, all the products have the same MAC Address that is changed at end of line, the boards use ...
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1answer
21 views

Infiniband switch, uplink

Regarding switches like Mellanox Voltaire VLT-30011 (QDR IB, managed). I see a gigabit ethernet port on the switch which in the manual ...
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1answer
42 views

Linux server as router emulating commercial modem [closed]

When you buy some commercial routers like TP-LINK or Buffalo or many others, you have the chance of connect to a wan network. So if in a commercial router I set the IP Address 192.168.0.2 and ...
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How to test/debug bad network wiring?

I recently bought a place already wired with Cat 5E (8 ports, leading to a central closet). However attempting to get link, nothing works. On closer examination, it was obvious that the ends in the ...
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3answers
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What is this wiring panel and what are these Ethernet “ports?”

In my office's building there is a stone-age LAN rack with some Ethernet ports I've never seen before. I need to find the name of this ports, if they have one, and then buy some cables or adapters. ...
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4answers
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Ubuntu Server, 2 Ethernet Devices, Same Gateway - Want to force internet traffic through 1 device (or at least allow it to work!)

I have a Ubuntu 10.04 Server with 2 ethernet devices, eth0 and eth1. eth0 has a static IP of 192.168.1.210 eth1 has a static IP if 192.168.1.211 The DHCP server (which also serves as the internet ...
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1answer
16 views

Can we use a ADSL2+ modem in bridged mode to convert to ethernet WAN? [closed]

I am no networking master, so I have no clue if this makes sense. I have a DSL line from my internet provider with all the service details. Now, I have a TP-Link modem (+router) WD8961N. This is ...
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1answer
31 views

route table issue when I appended option net.ifnames=0 to grub2

I appended two options net.ifnames=0 biosdevname=0 to grub2 because I want to change default network name to old name eth0 on RHEL 7. After that, I edited /etc/sysconfig/network to set default ...
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33 views

Making shared drives available on wifi?

I'm setting up a small office network. We have a raid connected to an ethernet switch, and that is accessible by all PCs connected to that network. My problems start when I tired to provide access to ...
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29 views

10gb ethernet direct connection (no switch)

Im trying to connect 2 computers with 2 PCIe "Core 4 HP 671798-001 HP CX-2 NIC 1 PORT 10GB" I'm using a SFP+ Direct Attach Copper Cable (I think they are also called twinax) I found a similar ...
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2answers
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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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How to dynamically find the name and type of interfaces attached to a system

I have a use case where I need to dynamically configure some files which includes the name of the interfaces present in system say eth0 , wlan0 . However when I change the system sometimes its changed ...
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4answers
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What happens when ARP Request comes from a different subnet?

What will happen when an ARP Request packet is sent from router1 to router2 in the following two cases? Will an ARP Reply be generated or the ARP Request packet be dropped? ...
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1answer
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how to disable ethernet interface eth5 permanently and how my added routes in rc.local file is unset when i reboot machine

actually my machine having 3 interface cards eth0 eth4 eth5 where eth0--local ip and eth4--wan Ip1 and eth5--wan ip5 but i want to disable permanent eth5 and i have added some routes in rc,local file ...
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5answers
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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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2answers
90 views

How to install USB-to-Ethernet Adapter on Windows Server 2012 [closed]

I am having problems installing a USB-to-Ethernet (model HB-T66) on my HP ProLiant ML310e Gen8 v2 server (Intel Xeon) running Windows Server 2012 R2 Standard. In Device Manager, the device appears at ...
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2answers
212 views

Is it possible having two Ethernet connections simultaneously on the same UTP Cat6 cable? [closed]

Actually it is a two part question. 1.Since an ethernet connection only requires 2 pairs (green and orange), is it feasible to wire blue and brown pairs to a different Lan port of a router and ...
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0answers
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Sudden failure of networking interface on CentOS 7

We're running a LAMP stack VPS on CentOS 7 hosting a few websites, MariaDB databases, and associated services. In the middle of the night our server mysteriously went completely offline. When we ...
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3answers
1k 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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1answer
44 views

Router - huge difference in Tx vs. Rx

I have two computers: (B) Banana Pi - 1 Gigabit Ethernet, Wi-Fi (supports 802.11n) (D) Desktop PC - 1 Gigabit Ethernet, Wi-Fi (2x2 MIMO, supports 802.11n) And (R) Mikrotik RouterBOARD RB951G-2HnD ...
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1answer
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Is PoE 802.3af Compatible with 802.3at?

If I connect a device that is compliant with POE 802.3af (surveillance camera) to a device (switch) which is POE 802.3at. It will work?
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231 views

Should I use a straight-through or cross-over for router to extender cabling?

I'm trying to conncect a router to a repeater (extender) should I use a straight-through or cross-over for the ethernet?
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Weird network interrupt issue

in ifconfig output i am seeing Interrupt 16 but when i check in /proc/irq/ i am not seeing number 16 there. following number i am seeing here. my driver is broadcom tg3 [root@centos7 ~]# ls ...
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What is the clock frequency inside 10Gb and 100Gb Ethernet cards?

As I understand, a 10Gb Ethernet card is capable of putting 10Gb every second on (say) a fibre optics cable. Now naively, for this to happen in hardware, one will need a 10GHz clock running the ...
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6answers
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My wireless is faster than my lan by a lot… why?

At my job the wireless is pulling download speeds of 11mbps and uploading at 2mbps. The lan however is averaging around 2-5mbps download and 1-2mbps upload. Our setup is pretty basic, a cable modem, ...
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What is the “in-the-wire” size of a ethernet frame? 1518 or 1542?

According to the table here, it says that MTU = 1500 bytes and that the payload part is 1500 - 42 bytes or 1458 bytes (<- this is actually wrong!). Now on top of that you have to add IPv4 and UDP ...
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802.1q VLAN echo replies do not include VLAN ID

I am running a SLES11, SP4 kernel on 2 systems. I have 2 NICs connected through a Netgear GS724T switch. I have configured VLAN 400 on the switch. On system 1, I create a VLAN 400 on eth0 called ...
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2answers
117 views

can two nic have same subnet but different network? [closed]

Business case: A computer has eth0 and eth1 and eth0 address is 192.168.1.2 (static). The eth0 is used by a configuration software to configure the address of eth1 in the field. eth0 is only for ...
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2answers
751 views

Alternative options for ethernet over 75 ohm coax?

I'm in need of running ethernet between nodes in an older brick, steel & mortar building where 802.11* at any power just simply stinks, and no we can't run CAT5 through the walls. Primarily this ...
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183 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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Packet drops after configuring Ethernet Bonding

I am trying to configure Ethernet bonding for our servers . Both the Ethernet interface in my server are connected to two different network switches physically. Looks like my Ethernet bonding ...
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1answer
587 views

How to stop ethernet interface in bridge configuration from obtaining IP address via DHCP

I'm trying to configure openvpn in bridging configuration. First step of doing this requires creating bridge interface (br0), bridging together physical ethernet interface (eth0) and logical tap0 ...
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48 views

10GB Ethernet latency, unsaturated cross-connect

I'm using shared (between few clients of a vendor) 10GB cross-connect in exchange data center. We receive few multicast data streams (each stream delivers data on some group of "stocks"/derivatives). ...
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230 views

*-network UNCLAIMED : How can I fix this issue

Out of the blue my second ethernet port stopped working. Both of them are part of the motherboard. I can see both of the ports in bios. They were working, but I was using only one of them up to now. ...
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1answer
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Client not getting address from some DHCP server

I'm working on some embedded devices which should be connected to a large network (hundreds of devices) via ethernet and that should be configured using the DHCP protocol. What I'm experiencing is ...
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6answers
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Cheapest way to remotely control 120v outlet via ethernet?

What is the cheapest solution to be able to remotely power cycle a regular 120V outlet via ethernet? I've seen solutions like iBoot, but they're really expensive. Is there a cheap way to remotely ...
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1k 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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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
203 views

100BASE-FX single-mode, confusing distances

I'm new to Ethernet over Fiber, so please bear with me. According to the standard, 100BASE-FX over SMF supports distances up to 10 Km. Technical documentation of some products states support for ...
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71 views

ensure “switch redundancy” on a network

I'm struggling in connecting two Windows 7 PCs (each with a 2 port Intel NIC) via two complete redundant paths. And I want to make it transparent to the services on that system. I was thinking on ...
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1answer
99 views

Windows Server 2012 r2 standard with dual NIC + DHCP

Currently I have a physical host with Windows Server 2012 r2 standard installed and DHCP role enabled. In addition the physical host has two network interface cards. I am planing to connect the ...
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Mismatch between IP address and MAC Address

Suppose you have two interfaces in the host belonging to the same subnet connected to a normal L2/L3 switch port which has a single vlan with interface IP 10.0.0.1. nxge0 (10.0.0.201) ...
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212 views

Color coding to connect rj45 socket and rj45 connector to make an ethernet extension cable [closed]

i want to make a cable like this: What should be the color coding to make this Ethernet LAN Network extension Cable. I have a rj45 socket and a rj45 connector but there indicator on rj45 female ...
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1answer
88 views

How to Find and Expose the Ethernet Interfaces in a RHEL5 Iimage dd-ed to a Different Machine

We captured the disk image off an IBM PS-703 (P-Series, i.e. Power-PC) BladeCenter using dd. in rescue mode. The image is RedHat 5.11. The goals were to have a backup image of the server and to be ...
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How can i disable reverse path filter rp_filter in mac

I am following this Ubuntu Linux - two interfaces, same subnet, different vlan - MAC/ARP issues # sysctl -w net.ipv4.conf.eth1/102.rp_filter=0 # sysctl -w net.ipv4.conf.eth1/103.rp_filter=0 But ...
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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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How to diagnostic internet access failure on a linux system?

I have a VM running on Xen. The virtual machine was running fine for months and suddently the network access broke down. Dom0 DomU .-------. bridge ...
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“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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185 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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2answers
260 views

Lightning/surge risk of Ethernet cable run inside an exterior wall [closed]

In a previous question, I had planned a Cat6 (Ethernet) cable run outside a home, adjacent to a coax run. I was advised against it, and I'm interested in taking that advice. Now I'm considering ...