Questions tagged as ['ethernet']

Ethernet is the most common set of standards for wired connections in local area networks.
Score: 0
dranobob avatar
How to view current PHY master-slave settings in Linux (Centos Stream)
in flag

I am trying to view the current master-slave settings on my network cards (HPs with Intel controllers).

I see ethtool has the master-slave option to set the mode, but I didn't see how to view the current setting. When I try only "ethtool " it doesn't show any master-slave settings.

Score: 0
yucer avatar
Can't connect ssh via wireless interface but t works using eth0
in flag

Suddenly I can't connect via ssh to a server using my wireless interface but I can do it using the eth0 interface with a cable connected directly to my router.

From my wireless interface I got:

$ ssh -vvv my_server
OpenSSH_8.9p1 Ubuntu-3, OpenSSL 3.0.2 15 Mar 2022
debug1: Reading configuration data /home/user/.ssh/config
debug1: /home/user/.ssh/config line 38: Applying options for my_server
debug1: ...
Score: -2
Zeghra avatar
net server ip connection fail etimedout
cn flag

I use nodejs net ( to connect pc as client to server via ethernet cable. The app connects well from one pc to server (ip, but it does not connect (etimedout) to server on another pc. First, I couldn't even ping the ip address of server, but setting on pc the ipv4 to it could ping the server, but still got etimedout. From nmap this could ...

Score: 0
Dave avatar
Can ping OPC UA server, but cannot connect to it
mk flag

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 the components and installing a new ethernet cable, I cannot connect to the server any more:

GetEndpoints on EndpointUrl failed with 'BadTimeout', retrying on all DiscoveryUrls
Could not connect to ser ...
Score: 0
Accessing Marvell switch via remote management interface
us flag

I have 88E6341 Marvell Ethernet switch.

I cannot access its MDIO and according to the datasheet the switch has remote management via Ethernet which I'm interested to use to diagnose connectivity issues.

What SW tools can I use on Windows or Linux to access switch registers?

Score: 2
Martin Pecka avatar
How to simulate what happens inside the packet buffer of a simple switch?
ro flag

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 simple - two bursty data streams come through 2 ports inside the switch and both want to leave it via a third port (common to both). So the switch needs to hold some data in the packet buffer for a whi ...

Score: 0
Event driven way to detect Ethernet port status changes (disconnected / 10mb / 100mb / etc) in linux?
pt flag

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 / 100mbit / etc.

We could just pool the status of the port every X ms, but I was hoping on using inotify to watch for something that changes on the filesystem and trigger our action based on that.

We are actua ...

Score: 0
Lunde avatar
Filtering traffic between ports on an ethernet switch
jp flag

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 with IEEE 802.1X (ACL) and 802.1Q (VLAN) support. What I specifically need is the following:

I need to only allow traffic from port 1 to 2 for one specific IP address. The same from port 2 to port 1, o ...

Score: 0
Lunde avatar
Limiting hosts on a network
jp flag

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: Network The ethernet switches are from Microchip, model KSZ9897, which is a managed layer 2 switch. The switch has multiple features, for example it supports IEEE 802.1X (port-based authentication and Access Control List (ACL) filtering) and IEEE 802.1Q (VLAN). All hosts are W ...

Score: 9
What Ethernet twisted pair cable is best with a particular Ethernet switch
ph flag

tl;dr I want the best supported Ethernet cable for my Ethernet switch. How do I correlate Ethernet cabling speeds measured in hertz with an Ethernet switch "speed" measured in bits-per-second bandwidth?

There are several Ethernet twisted pair cabling standards; "Cat 5e", "Cat 6", "Cat 6A", "Cat 7", etc. each supporting a maximum length and hertz rating. For example, according to Wikipedia "Cat 5e ...

Score: -1
Henry avatar
Onboard ethernet versus Intel NIC
cn flag

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. Payload of around 100 KB per message,
  2. Frequency of around 1000 messages per second maximum,
  3. Ideally, the handling of these messages should consume CPU time as minimum as possible (the CPU will be used fo ...
Score: 0
Simon Fromme avatar
Network layer communication with multiple hosts with the same IP but different MAC addresses
cn flag

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, all hosts have unique and known MAC addresses and are in the same broadcast domain. Is it possible to communicate with the hosts individually and simultaneously on the IP-level by crafting the corresponding  ...

Score: 0
user236012 avatar
Gateway with multiple VLAN IPs on one NIC
cn flag

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. My idea is to use a switch that supports VLANs, and build up the network like this:

enter image description here

P1 and P2, P3 and P4 are four different hosts that belong to two separate, "physical" networks (VLAN 1 and 2). They should be protec ...

Score: -1
Bruno Schroeder avatar
Mac can be arpinged but not pinged
ng flag

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 2015). I am researching on how to debug the his adapter. Ethernet lights blink but I don’t know enough about this early FireWire.

With a simple Netgear four ports switch-hub, when connecting via RJ45 ca ...

Score: 18
What can cause network packets consisting of PUU?
us flag

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 NICs and cables throughout - or so I am told by the customer who built the network we are plugging into.

We plugged in a laptop running Wireshark via a 100baseT hub and found that it reported lots of ...

Score: 0
Norbox avatar
Raspberry Pi as internet forwarder
in flag

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 be more private device and I can't find any information if it's even possible. So I thought about connecting internet cable to rpi, turning on vpn and then connecting second internet cable to another etherne ...

Score: -1
Farhan Ghazali avatar
Converting phone wall mount to ethernet mount
uz flag

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 this cable be converted to ethernet so that I can connect my pc in another room using ethernet straight to the router?

I attached some photos. Room Near Router

Score: 0
NK-cell avatar
Is there a way to configure port security on Linux bridge?
in flag

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 Ethernet frames from some new device will be blocked.

So is there a way to do it in Linux bridge?

This post didn't help.

Score: 5
HeyHelpDeskGuy avatar
Can tone ethernet cable into patch panel but it's not working
sa flag

So we recently had to two major issues happen at a location.

  1. We had a lightning strike hit the building
  2. We updated switches after this lightning strike

Now one thing that was 'hit' was a SOHO router. After upgrading the server room, we realized that the port for this SOHO router no longer works. I toned the cable out fine but the replacement router (same make & model) isn't powering on. I've r ...

Score: 2
NeroP avatar
No responses to ARP requests
au flag

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 I look at a capture of traffic on the bridge br0, I see a lot of ARP requests from the server and VM, but no responses at all. This only affects IPv4.

Restarting the switch attached to eno3 doesn't hel ...

Score: 0
Security issues with configuring default IP address( to ethernet interface
ca flag

In our linux embedded application we would like to keep available ports up and running and assigning with IP address. In short we will be executing all ports with ifconfig ethX, and setting all IP address to virtual interfaces ethX:100 is there any security issues with configuring ethX to Is there any other issue can be faced if we configure all IP address on virtual  ...

Score: 0
user3742046 avatar
SQL server connection TCP/IP overt Ethernet
pf flag

I have two PCs. There is SQL Express installed on one of them. TCP/IP settins are here:

tcp/ip settings tcp/ip settings

tcp/ip settings tcp/ip settings

When I perform Test-NetConnection on local computer I get local

But when I do it from remote PC I get remote

As you can see tcp succeeds when connected over WiFi but fails over Ethernet. Ping is OK but TCP/IP connection fails. I tried many different ports with same results. I'd be grateful fo ...

Score: 0
A. Petrov avatar
Is there exist in a market some usb->ethernet->wifi combo dongle?
cn flag

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 this device connected to the network via USB-to-Ethernet adapter in a wall-mounted RJ45. Furthermore, is there any combo device in a market which can act as USB-to-Ethernet from one side and in the s ...

Score: 0
Qlogic QLE8152 connect to a DS14 disk shelf
gg flag

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 not connect, I see that the DS14 supports max of 2gbps, however the adapter is listed as a 10gbps one, any ideas how to configure it to a lower speed?

I tried setting it via ethtool

sudo ethtool -s [device_ ...
Score: 0
Ethernet/UIB device is accessible on one system but not the other (Linux)
gb flag

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 through/dev/ttyACM0

arp -a
( at d8:80:39:27:d5:4b [ether] on eth1

On the other system (B), the device is visible, yet its MAC address is hidden and it is not possible to establish a connec ...