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Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

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Archive for the ‘Ethernet’ Category

Raspberry Pi cannot be woken up by WOL, but it can send, and there is Whack-on-LAN

Posted by jpluimers on 2019/01/17

Cool stuff if you want to make your own WOL devices out of spare parts.

From old to new:

They can be woken up by anything sending magic WOL packets, including Raspberry Pi (which cannot be woken up by them, though you could use a Whack-on-LAN for that).

Basically the Raspberry Pi cannot be woken up with WOL because of a few reasons:

  1. The ethernet chip is connected over USB so it cannot pass the WOL result further on.
  2. If it could, there still is no BIOS to process the WOL result.
  3. When it is halted but has power, the CPU isn’t active. The GPU is, but cannot process the WOL.

It can be a WOL server though: [WayBackRaspberry Pi As Wake on LAN Server: 5 Steps (with Pictures)

–jeroen

Posted in Development, Ethernet, Hardware Development, Network-and-equipment, Power User, Raspberry Pi, Wake-on-LAN (WoL) | Leave a Comment »

Strange MAC addresses starting FA:8F:CA without OUI in your network? They are Locally Administered Addresses and likely from Google.

Posted by jpluimers on 2019/01/07

A while ago, I write about Locally Administered Addresses: a few series of MAC addresses you can use on your local network: MAC address ranges safe for testing purposes (Locally Administered Address).

A while ago, I found ones in my network and ones in my WiFi SSID survey starting with FA:8F:CA. They did not show up in the Wireshark · OUI Lookup Tool nor their manufacturer database.

But with bit 7 turned off they start with F8:8F:CA which does show up as “F8:8F:CA Google, Inc.”

They appear to be Google devices, in my case Google ChromeCast ones, though they can also be Google Home ones.

Google does “magic” with networks, just look at a few of the links here:

–jeroen

Posted in Ethernet, Google, Internet, Network-and-equipment, Power User, Ubiquiti, WiFi | Leave a Comment »

Going to test some USB 3 gigabit ethernet adapters based on Realtek RTL8153 and Asix AX88179 chips

Posted by jpluimers on 2018/07/27

Later on, I might add a USB31000S in the mix, but I will do some initial testing with USB 3 gigabit ethernet adapters based on Realtek RTL8153 and Asix AX88179 chips.

Things I will focus on with my Retina MacBook Pro 2015 model are:

  • CPU usage
  • Throughput
  • Duration between reconnect on USB after suspend, and renewing the DHCP lease
  • Promiscuous mode capabilities

Some links for my references:

A first impression from the above links is that for Realtek chipset based devices, drivers are more readily included in operating systems, and these chipsets are better at VLAN handling.

–jeroen

Posted in Ethernet, LifeHacker, Network-and-equipment, Power User, USB, USB, USB-C | Leave a Comment »

MAC address ranges safe for testing purposes (Locally Administered Address)

Posted by jpluimers on 2017/10/25

Similar to IP ranges for private networks that are safe for testing

  • 10.0.0.0/8 (255.0.0.0)
  • 172.16.0.0/12 (255.240.0.0)
  • 192.168.0.0/16 (255.255.0.0)
  • fd00::/8

there are also locally administered MAC address ranges safe for testing

  • x2:xx:xx:xx:xx:xx
  • x6:xx:xx:xx:xx:xx
  • xA:xx:xx:xx:xx:xx
  • xE:xx:xx:xx:xx:xx

Thanks to [WayBack] Sam and [WayBackPeter for answering.

–jeroen

References:

Posted in Ethernet, Internet, Network-and-equipment, Power User | Leave a Comment »

T568A and T568B termination – TIA/EIA-568 – Wikipedia

Posted by jpluimers on 2017/08/04

As I always forget the images on UTP wireing in both connectors and outlets and forget which standard is T568A and T568B: T568A and T568B termination – TIA/EIA-568 – Wikipedia:

Pin T568A Pair T568B Pair 10BASE-T 100BASE-TX 1000BASE-T Signal ID Wire T568A Color T568B Color Pins on plug face (socket is reversed)
1 3 2 TX+ DA+ tip Pair 3 Tip
white/green stripe
Pair 2 Tip
white/orange stripe
Rj45plug-8p8c.png
2 3 2 TX- DA- ring Pair 3 Ring
green solid
Pair 2 Ring
orange solid
3 2 3 RX+ DB+ tip Pair 2 Tip
white/orange stripe
Pair 3 Tip
white/green stripe
4 1 1 DC+ ring Pair 1 Ring
blue solid
Pair 1 Ring
blue solid
5 1 1 DC- tip Pair 1 Tip
white/blue stripe
Pair 1 Tip
white/blue stripe
6 2 3 RX- DB- ring Pair 2 Ring
orange solid
Pair 3 Ring
green solid
7 4 4 DD+ tip Pair 4 Tip
white/brown stripe
Pair 4 Tip
white/brown stripe
8 4 4 DD- ring Pair 4 Ring
brown solid
Pair 4 Ring
brown solid

Note that the only difference between T568A and T568B is that pairs 2 and 3 (orange and green) are swapped.

For cross-over cables (used less and less because of Auto MDI-X which is standard in 10000BASE-T) this is slightly different Appendix B: Ethernet Crossover Cables – Configuring and Troubleshooting Ethernet 10/100/1000Mb Half/Full Duplex Auto-Negotiation – Cisco [WayBack]:

Four Twisted-Pair Crossover Cable Schematics for 10/100/1000 and 1000BASE-T GBIC Module Ports

3a.gif

3c.gif

There are some nice colour coded wiring diagrams at Tech Stuff – LAN Wiring and Pinouts [WayBack] for both straight wiring [WayBack] and crossed wiring [WayBack]:

All work fine for CAT5, CAT5E and CAT6.

–jeroen

Posted in Ethernet, Network-and-equipment, Power User | Leave a Comment »

 
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