Networking – layer 2 communication.

Compute networking sometimes gives new ITers a feeling of confusion and complication when they start learning networking, this post will simply explain it in laymen terms and provide a basic concept and some basic configuration on Cisco productions for reference.

So what is layer 2 communication? What does it provide or allow us to do? What is networking HUB and what can it do? What is the different between network switches? What are LAN and what are VLANs? (This post will explain the ethernet network only) Continue reading


Turning Raspberry PI into WIFI AP (in bridge mode)


Turning raspberry PI into WIFI AP: SSG5 to SRX migration (part 2)

Due to the insecure of internet platform, I have decided to run a security appliance at home to replace my SSG firewall. My newest design is to have SRX as the SSG replacment. Since SRX lacks of the feature of build-in WIFI, I have decided to use RASPBERRY PI as the WIFI AP bridge to cover the wireless access feature. In part 2 of this migration, it mainly focus on turning the RASPBERRY PI as the WIFI AP and bridge it to its ETH0 interface.

The WIFI AP elements:
– Raspberry PI model B
– 0ace:1215 ZyDAS ZD1211B 802.11g

Design for PI:
– Since the ESXi host is using trunk, the PI needs to have its NIC ready to take tagged and untag packets.
– PI turns the WIFI NIC into WIFI access point
– PI needs to bridge the ETH NIC and WIFI NIC to extend the SRX LAN boardcast domain with wireless capability.

Continue reading