networking

WiFi for a Small Tech Conference/Meetup

WiFi Routers - AirPort Extreme and AirPort Express

WiFi is awesome for homes and small businesses. Stick a router in a closet somewhere near where you have a cable modem or DSL router, and—boom!—easy Internet and Network access for all 5-10 people/devices within the building.

But, try bringing this setup to a small conference or a meeting of 25+ (or 200+) computer-using people, and you're in for a world of hurt. Some people will get slower-than-dialup access, some people won't be able to connect at all, and others will have strange issues that never happen when you're just using the network by yourself.

The problem(s)

There are many problems that cause WiFi to fail in any setting with more than a few people/devices:

AirPort Express - Flashing Yellow Light, Not Getting DHCP Address from Cable Modem

I spent the greater part of this afternoon trying to get my AirPort Express to connect to the Internet and share an IP address using a Motorola SB5101 Cable modem (with Charter Internet)... and since the solution was so simple and annoyingly stupid, I thought I'd post it here, for my reference and for anyone else spending an afternoon thinking his AirPort Express is dead.

As it turns out, the cable modem (this one, and likely many others) will only remember the MAC address of the first device it recognized when you last power cycled the modem.

When the Internet went down at my condo yesterday, I turned off my cable modem, plugged my Mac straight into it, turned the modem on, and use the internet via this direct connection for a while. When I plugged the AirPort Express back into the SB5101, I just got a flashing yellow (amber) light, and in the Airport Utility, a notice that the 'Internet Connection wasn't working'.

XLR over Cat5 - Balanced XLR Mic-Level & Line-Level Audio over Cat5 & Cat5e Cabling

Cat5 Cable with XLR Audio Jacks

The challenge: Run two 200' cable runs for VOX (2-way communication via headsets) and an ambient microphone. Mics and headsets to be used for broadcast of major event via satellite, web, and all major local news outlets.

Limitations: Extremely tight budget for cable + installation, two weeks to install and test, 100 year old stone/masonry building, skeleton crew of volunteers.

Solution:

  • Run readily-available Cat5e (shielded, solid) network cable to two VOX/mic locations (we had a box with a few hundred feet left inside, and we bought another 500' box (extra == always better) for $100. (Check Amazon for bulk Cat5e cable).
  • Use custom faceplates with two XLR jacks—female for VOX headsets, female for Mic input
  • Cross fingers, and hope it works.

Share a Proxied Network Connection via WiFi to your iPad/iPhone/iPod

For the past six weeks that I've had my iPad, I've fought with my office network, because it uses a Microsoft/NTLM authenticated proxy server which wreaks havoc on the iPhone OS's ability to use the Internet effectively (especially for third party apps).

After reading through countless forum support requests for people asking the same questions, I've finally found a (mostly) workable solution for this problem—at least for most apps and browsing on the iPad.

Doubling the Proxy

Since the iPhone OS seems to have a pretty hard time dealing with proxy authentication (most apps don't act like there's even an internet connection, even if Safari will work through the proxy), I used a solution I often use on my Macs at work: doubling up the proxy.

Basically, you can use an application like Authoxy on the Mac to make the Mac translate all its web traffic through a special internal connection, which gets messaged correctly by Authoxy to work with your company's proxy server.

SSH in a Locked-Down Network

Recently, during one job for a client, I needed to work for a length of time in a location that had quite severe network restrictions—in addition to a proxy server, the location blocked every port besides 80, 25, 443, and 8080. In order to use secure shell (SSH) to login to my work web server, I needed to use one of those ports (I used nmap to find open ports on my end).

Luckily, I gained access to another network for a short time, and used that connection to update my work web server to allow SSH over port 8080 (in addition to the standard, port 22). I edited the /etc/ssh/sshd_config file so it reads:

Port 22
Port 8080

(the Port 22 line was commented out, originally).

Then I simply used the -p (port) directive when logging in via SSH:

$ ssh -p8080 username@example.com