Questions tagged [ethernet]

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

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Access mysql from another computer connected with crossover cable

I have two computers, and i am trying to access mysql via network on port 3322 (mysql listens on this port) Computer A Server: Windows 10 home Added firewall exception to port 3322 (mysql installed ...
13 votes
6 answers
21k views

Why does ethernet have a minimum frame size specified?

I think the minimum is 64 Bytes. Why is that minimum necessary?
0 votes
1 answer
1k views

Can ping OPC UA server, but cannot connect to it

I have an OPC UA server running on a PLC from BR Automation and would like to connect to it from UaExpert running on a Windows 10 machine. It has worked previously, but after physical re-placement of ...
0 votes
2 answers
127 views

Why is my client still talking to my server when I change client IP to different subnet? [closed]

On occasion, I'm using a Verizon Mifi adapter to share an internet connection over my office network (which doesn't have internet). To do this, I have to share the internet connection on the adaptor, ...
2 votes
0 answers
664 views

How to simulate what happens inside the packet buffer of a simple switch?

I'm debugging a case of UDP packets lost in a store-and-forward gigabit switch and I wanted to visualize what happens inside the switch to better understand the gist of the problem. The scenario is ...
0 votes
0 answers
379 views

Event driven way to detect Ethernet port status changes (disconnected / 10mb / 100mb / etc) in linux?

I was wondering if linux has some sort of interface to detect ethernet port state changes via /sys or some other way that is event driven. What I mean by state changes is DISCONNECTED / 10mbit / ...
22 votes
2 answers
20k 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 ...
1 vote
1 answer
1k views

Filtering traffic between ports on an ethernet switch

I would like to know if there is a standard way of limiting traffic between ports on a managed Ethernet switch? I have a 7-port Ethernet switch (microchip - KSZ9897), which is a layer 2 switch, but ...
0 votes
1 answer
148 views

Limiting hosts on a network

I am in need of some networking advice and hopefully some of you will be able to help me. My network is shown in this block diagram: The ethernet switches are from Microchip, model KSZ9897, which is ...
2 votes
1 answer
4k views

Where to find list of possible arguments for ethtool -K?

When I want to disable/enable interface features with the ethtool -K command, how can I list all available options? When I run ethtool -k I see a list of options, but I don't know the equivalent ...
54 votes
6 answers
93k 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 ...
0 votes
2 answers
2k views

Onboard ethernet versus Intel NIC

I would need some recommendation about the benefits of using a dedicated Intel Ethernet card versus simply using the integrated Ethernet of the motherboard. The typical use case would be the following:...
-1 votes
2 answers
161 views

Mac can be arpinged but not pinged

Why does Mac OS X and Linux do not ping each other on a local Ethernet Network? Edit 2012-12-14 (ten days latter) adapter FireWire to Ethernet RJ45 might be the problem (on MacBook Pro Retina early ...
0 votes
3 answers
501 views

Network layer communication with multiple hosts with the same IP but different MAC addresses

Due to an unfortunate (mis-)configuration issue I am having ~100 hosts of which the IPv6/IPv4 (even the IPv6 link-local) addresses are all the same and which for the moment I cannot change. However, ...
0 votes
1 answer
595 views

Ethernet patch or crossover router to router [closed]

I we have run Ethernet in the house, through a fast Ethernet switch, through a wall patch, over the river and through the woods as it were. From router A, through switch, through wall patch, then to ...
0 votes
2 answers
820 views

Gateway with multiple VLAN IPs on one NIC

I would like to separate several hosts from the local network and put them behind a firewall. I would like to use VLANs to "physically" separate them instead of using just different subnets. ...
2 votes
0 answers
467 views

No responses to ARP requests

One of my server's physical interfaces eno3 is part of a bridge br0. There is also one LXD machine attached to this bridge (nictype=bridged, parent=br0). Sometimes ARP stops functioning completely. If ...
18 votes
4 answers
2k views

What can cause network packets consisting of PUU?

We have a system which is suffering from comms outages on a gigabit ethernet network. The traffic load on the network is such as to slightly stress a 100Mb network, but there are gigabit switches and ...
4 votes
3 answers
11k views

Is it safe to connect a PoE injector switch to an ordinary PC?

Is it safe to connect a 24 V PoE switch output to an ordinary PC Ethernet input?
0 votes
1 answer
119 views

Raspberry Pi as internet forwarder [closed]

I thought about building a device that will behave as a forwarder with VPN. I know that I can e.g. take the internet cable, connect it to rpi, turn on vpn and create wifi hotspot. But I wanted it to ...
-1 votes
1 answer
33 views

Converting phone wall mount to ethernet mount [closed]

I currently have a telephone wall mount. 1 near the router, 2 more in another 2 rooms. When I remove the wall mount, I can see 4 wires from the cable. Red, Blue, White and Grey. My question is, can ...
0 votes
1 answer
422 views

Is there a way to configure port security on Linux bridge?

On switches there is such a feature as Port Security. Roughly speaking it allows to control, which exactly MAC's can be on the specific switch port. You can restrict it to just one MAC or several, and ...
5 votes
3 answers
5k views

ethernet smp_affinity vs /proc/interrupts vs /sys/class/net/ethX/device

My goal is to configure our CentOS ("free" RHEL) 5.x servers for custom low-latency network programs. I would like to experiment with binding ethernet NIC interrupt handling to the same CPU on which ...
1 vote
3 answers
12k views

Do all ethernet switches support multicast?

I'm playing with LANs here at home and I want to support multicast. Do all switches nowadays support multicast? Even the cheap ones? I'm buying a 5-port gigabit switch. Will it support multicast?
5 votes
2 answers
2k views

Can tone ethernet cable into patch panel but it's not working

So we recently had to two major issues happen at a location. We had a lightning strike hit the building We updated switches after this lightning strike Now one thing that was 'hit' was a SOHO router....
3 votes
2 answers
19k views

Can't start eth1 and dhcp on debian wheezy

What I want: eth0 is connected to internet and has a static IP-address. eth1 connected to internal network and be a dhcp server for subnet. But I can't get eth1 to work. Error: $ ifup eth1 Missing ...
2 votes
0 answers
1k views

How to manually setup Whonix networks for QEMU?

I would like to run Whonix directly using QEMU instead of using libvirt and I want to manually setup internal and external network. Using libvirt I would need to run those commands: virsh net-define ...
0 votes
0 answers
146 views

Security issues with configuring default IP address(0.0.0.0) to ethernet interface

In our linux embedded application we would like to keep available ports up and running and assigning with 0.0.0.0 IP address. In short we will be executing all ports with ifconfig ethX 0.0.0.0, and ...
0 votes
1 answer
142 views

SQL server connection TCP/IP overt Ethernet [closed]

I have two PCs. There is SQL Express installed on one of them. TCP/IP settins are here: tcp/ip settings tcp/ip settings When I perform Test-NetConnection on local computer I get But when I do it ...
0 votes
1 answer
77 views

Is there exist in a market some usb->ethernet->wifi combo dongle?

I have a USB-ended device which I want to connect to Enterprise Wireless network (EAP/TLS via FreeRadius). Is there any device in a market which can act as a WiFi client with EAP/TLS possibility? Now ...
0 votes
1 answer
128 views

Qlogic QLE8152 connect to a DS14 disk shelf

I am trying to configure a NETAPP DS14 disk shelf to expose the drives to a windows or a linux machine, I don't have a controller but I got a FC to ethernet adapter (Qlogic 8152) however the loop does ...
0 votes
0 answers
102 views

Ethernet/UIB device is accessible on one system but not the other (Linux)

A Universal Interface Board connects to the computer via Ethernet. On a correctly configured system (A), arp -a lists its MAC address and establishes a connection. The connection appears to happen ...
0 votes
0 answers
498 views

How to bridge two VMWare vsphere "VM Network" on two different site?

I got Two sites with some ESXi 6.7. Each site has its own IP address and I would like to bridge the "VM Network" on the distant site to the local "VM Network" so I could start a VM ...
0 votes
1 answer
896 views

Windows 10 multiple Ethernet connections with one being connected to the internet but PC doesnt connect to the internet [closed]

I have a win10 machine in a rural area with no ability to connect to a private network. The computer is used to track measurements of specific sensors which are connected with ethernet to the computer....
-2 votes
1 answer
2k views

What transceiver can convert 10GBASE-KR or 10GBASE-KX4 to 10GBASE-T or 1000BASE-KX to 1GBASE-T? [closed]

A pci-e network card supports 1000BASE-KX, 10GBASE-KX4 and 10GBASE-KR on SFP connector, but the required mode for twisted pair support on RJ45 (8P8C connector) is 1G- or 10GBASE-T. What type of ...
2 votes
1 answer
733 views

My network interface changes names, so DHCP / dhclient cannot operate on it

On some ArchLinux servers I've switched from dhcpcd to dhclient, but the servers are not receiving IP. Upon inspection with journalctl I see that, on all occasions the IP was not received, dhclient ...
0 votes
1 answer
106 views

A simple configuration: LAN + direct connect simultaneously [closed]

This should be an easy configuration, but I'm struggling to Google for it; the vocabulary eludes me. I've got a desktop with onboard gigabit which finds its way to the internet via the router. ...
0 votes
1 answer
636 views

How is 10GBASE-T defined for providing compatibility?

Is there a common source for description (like for "data link layer" and might include electrical specification of "physical layer") of 10GBASE-T as standard for technical devices? Considering ...
-2 votes
2 answers
156 views

Are Dell parts compatible with non-Dell hardware? [closed]

I could not find the answer... I'm about to buy this piece: https://www.dell.com/pt-br/work/shop/intel-x710-10gb-sfp-mezzanine-adaptador-e-porta-dupla-da-dell/apd/555-bdpg/equipamentos-de-rede Will ...
1 vote
0 answers
44 views

Internet goes down when someone access our URL?

Setup: Have a metal server in our office closet, host OS is windows 10. It hosts 4 VMs, one of which is an internet facing application and accessible via URL. The server has 2 network cards, the first ...
1 vote
0 answers
172 views

Ubuntu Ethernet Duplex setting fault

I am trying to connect my Ubuntu 18.0.4 hardware to a managed switch that has the duplex set to Full and speed set to 100. The Switch cannot be configured to Auto mode because it is customer ...
0 votes
0 answers
111 views

Abnormal port request on Linux system

I am using Debian Buster and Android 9. Checking the network activities I noticed that it scans many ports. How can I determine who is the cause or if this is normal? I connect the mobile phone to the ...
-2 votes
1 answer
110 views

Can we have multiple IP addresses with different Net IDs on an interface? [closed]

Can we have multiple IP addresses with different Net IDs on an interface? Like a Network Card? For example setting up 192.168.1.2 and 18.170.2.5 on the same network card. If yes, where do we use this ...
1 vote
1 answer
395 views

Debian 10 backward compatibility with eth0

Noticed when upgrading to Debian 10 (Buster) that the public eth0 network interface is now called ens5 on AWS EC2. Is there a way to create a symbolic link or similar so that legacy applications that ...
0 votes
1 answer
1k views

Ethernet bond interface fails after NIC replacement

I've replaced a failing 10GbE adapter in a Dell PowerEdge server running a bonded pair of Cat6 cables to an aggregate switch. The old NIC and its replacement are both Intel Ethernet Controllers (10-...
3 votes
3 answers
2k views

How can I use iptables to drop packages for an invalid ether-type?

19:27:47.782291 98:9b:cb:: > ff:ff:ff:ff:ff:ff, ethertype Unknown (0x88e1), length 60: 0x0000: 0000 a000 b052 38e5 d57f 0000 0000 0000 .....R8......... 0x0010: 0000 0000 0000 ...
-1 votes
1 answer
85 views

Use ethernet port for smb share transfers, but smb should still be accessible over wifi [closed]

I'm pretty new to Linux networking and I'm not sure how to fix a file transfer issue I have. I have two Raspberry Pis. One is running Raspberry Pi OS and the other is running OSMC. Both are connected ...
0 votes
1 answer
869 views

LAN cable-tester's LEDs fire at 3 and 6 (without passive side attached)

I have hardware question. I am running a duplex CAT7 cable from a patch panel to a wall socket. One connection works, the other struggles when I test the cable. Below I describe how I tested the cable ...
1 vote
0 answers
45 views

Bringing interface up without a cable (but bridged VMs)

I've set up a bridged network vm (i.e. virtual network hub, vm:192.168.1.2, host real network card: 192.168.1.1) There's no network cable. As I do not care for one on this host->vm setup. The vm ...
0 votes
1 answer
1k views

dhcp-server + iptables: Can't share ppp internet connection

I had this configuration before, and it used to work well, but now I got a new server and I can't setup it to share the internet connection from ppp0. I'm on Debian testing. The client connects ...

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