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

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GRE protocol type for Ethernet over GRE?

For a IP over GRE tunnel, as defined by the RFC 2784, the "protocol" field is filled with 0x0800 (defined as ETH_P_IP in the Linux kernel according to this source ...
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16 views

Communication between two PCs [closed]

I need to make two PCs communicate using Ethernet connection. I am quite new to the field. I want to know what mechanism would be the best; Client-server, P2P, Uni-cast or multi-cast. Or the later two ...
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1answer
231 views

Ethernet cord not detecting in centos 7

Please help me out, the ethernet modules all are loaded but i could not find remaining the two ethernet ... [root@vpn ~]# lspci | grep -i ethernet 01:01.0 Ethernet controller: VIA Technologies, Inc. ...
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3answers
12k 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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0answers
16 views

Unable to Ping over wifi [duplicate]

We have 2 PCs and 4 laptops in the office, and we use D-Link 2750U to connect to internet. All the computers can connect to the internet successfully. One thing that I noticed recently, is that PCs ...
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3answers
6k views

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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4answers
2k views

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
42 views

Debugging why network packets are being dropped

Preface: I have an application that I am currently testing out that runs on RHEL 6. The setup for my test is the application installed on a embedded device, connected by an Ethernet cable to PC that ...
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2answers
73 views

Measuring 40Gbe performance

I've connected two hosts via a 40Gbe fibre link and would like to determine a baseline for data transfer between them. I'm seeing relatively low speeds (~620MB/s). It seems that the signalling rate is ...
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1answer
42 views

Need a program to check all Ethernet ports in my office for it's proper functioning [closed]

my office has a 20 Mbps leased line connection and we are using a firewall machine and unmanageable switches. Now the problem is the we are getting a very slow speed on all the nodes and we are unable ...
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8answers
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How to check the physical status of an ethernet port in Linux?

I want to check if a specified ethX is physically up or down. How do I do that with the command line?
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2answers
993 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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1answer
44 views

100BASE-FX WDM vs 100BASE-BX vs 100BASE-BX10 - Are they all the same?

Are these three all the same thing being inconsistently named by different manufacturers? 100BASE-FX WDM uses separate wavelengths (1310 nm & 1550 nm) for Tx & Rx over a single strand of ...
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2answers
26 views

Lan card not recognizing connected cable

I have a system with Ubuntu Server 14.04 installed on it. The onboard ethernet port is faulty. As I want to setup DHCP server on it, I have installed two external LAN cards. I also have a leased line. ...
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3answers
44 views

Network adapter only works with ethernet switch

I have a Dell XPS13(Win 10 Pro) and since we dont have wireless lan in the office i had to buy an external ethernet adapter (DA200). The adapter works perfectly fine at home but it doesnt work at all ...
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1answer
31 views

802.1Q and Network Security

I've recently purchased some TP-Link managed switches (two TL-SG1016DE and one TL-SG105E). I purchased the two first and set it up using 802.1Q VLANs to segregate my DMZ and my LAN, using ...
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2answers
104 views

Windows Limiting Internet Speed [closed]

I am currently experiencing a strange problem on my Windows Server 2012 R2. My whole network has been done with CAT6 UTP and everything (switches, adapter, etc) is able to do gigabit. My Internet ...
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0answers
46 views

Using LINK_REQUIRED parameter with wicked

I'm running SLES 12 and trying to configure network interfaces; this is my first experience with wicked. I'm using "ifup" to up the ethernet devices. I ran into an issue of not being able to ifup the ...
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7 views

Can't connect to the IBM bladcenter switch

I got IBM 8677 bladecenter with hs21 type 8853 & 7995 I connect the Ethernet SM I\O module , configed it in the IMM to same subnet as my host. I dont know why , but I cant telnet it or ping it . ...
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3answers
13k views

How to test cat5/cat6 cable runs, using software-only, or simple tools?

Are there any utilities or simple tools or techniques to easily test a CAT5 cable, to see how well was it installed? Cat5 is often installed by amateurs, but has been installed and "working" for ...
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1answer
48 views

Difference between 1.0 Gbps & Auto Negotiation [closed]

I am downloading a huge file and was wondering on how to boost my Ethernet speed. I found this option called "Speed & Duplex" And there were a few options. Two of them were 1) 1.0 Gbps Full ...
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2answers
75 views

Does a private MAC Address range exist?

I need a set of MAC/Ethernet addresses that I do not have to worry about collisions with, analogous to 192.168.x.x: addresses that will NEVER be assigned to real hardware.
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22 views

Connecting to sensors over LAN whilst using separate Wifi connection to post to cloud [closed]

I have a pc running a C# application. The application connects with an RFID sensor over ethernet and sends data to the cloud over wifi. Currently this solution requires a new ethernet switch be made ...
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4answers
523 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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33 views

Multiple IPv6 addresses added to interface, now IPv6 not working on my server [duplicate]

I got /64 IPv6 block from my server provider. When I add few IPv6 addresses (maybe 10 or 20) to network interface. Everything works fine about IPv6 network. When I'm added above 500+ IPv6 addresses ...
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1answer
100 views

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
70 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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3answers
9k views

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
2k views

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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1answer
28 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
42 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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36 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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71 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
1k views

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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1answer
103 views

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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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
25 views

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
297 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
283 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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81 views

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
109 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
22 views

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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1answer
482 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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28 views

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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2answers
4k views

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
469 views

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, ...
19
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4answers
15k views

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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0answers
67 views

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 ...