Basic-Talk initial testing

My wife has not really taken to cellphones and was never a fan of wireless phones. She prefers a POTS instrument. So I picked up a Basic-Talk from WalMart.

Registration was straight forward. So the next problem was connecting a copper ethernet.

At home, we're using a T-Mobile "hotspot", G4 cell-to-WiFi unit:

No copper ethernet interface.

My first attempt was to use our MacBook sharing the WiFi with the copper ethernet port. No luck, so I switched to an IBM ThinkPad running Debian Linux:

• NAT - already had it working
• DHCP - had to add it as the Basic-Talk insists on using bootp/DHCP to get an IP address and address of the DNS interface (i.e., the hot-spot IP)
• enable ip_forward - the last step, it connected and we're up

It rides on our broadband and operates a POTS instrument, ring and call. I don't have a caller-ID POTS phone in the house but this is a claimed capability. Too early to call it one way or the other. However, our last phone bill was $30/month and this unit claims less than $10/month. I may have to tweak the DHCP setup and verify a cold start brings everything up. But so far, it looks to be a practical solution.

For our purposes, a POTS like, cell-phone would meet my wife's expectations. Just transfer the SIM card and have a happy. But 'she who must be obeyed' gave me an ultimatum so the problem has been solved . . . good enough.

I will get a small UPS unit and organize a wireless setup with a single wall plug. The laptop and T-Mobile hot-spot both have batteries but the 12V powered, Basic-Talk does not. . . . More toys.

Bob Wilson

 

I think it is great to have so many options. In effect AT&T (formerly Bell South) is one of the best advocates for their competition . . . T-Mobile being our choice. So this morning, I've been fixing everything to come up after a reboot:

1. WiFi to come up after reboot without having to login
2. Find the WiFi device and the DNS IP address
3. Configure a static network on the copper, eth0 interface
4. DHCP to efficiently manage the copper ethernet
5. NAT required iptable setup
6. enable ip_forward part of reboot

Using GNOME, System->Preferences->Network Connections->Wireless, select the ESSID and 'edit' find the WiFi and enable "Available to all users" and hit 'Apply'. This sets the WiFi interface to come up automatically upon reboot without having to login. The IBM ThinkPad has a WiFi antenna icon and if this works, it will light by itself after a reboot.

First, find the WiFi interface and what it is using for the DNS server:

[pre]#​

root@bwilson:~# netstat -rn​

Kernel IP routing table​

Destination Gateway Genmask Flags MSS Window irtt Iface​

192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1​

192.168.254.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0​

0.0.0.0 192.168.0.1 0.0.0.0 UG 0 0 0 eth1​

# cat /etc/resolv.conf ​

# Generated by NetworkManager​

nameserver 192.168.0.1[/pre]​

So we find the WiFi is using device "eth1" and the DNS server address is the same as the WiFi routing interface. They can be different so check as these are needed later.

In /etc/network, edit 'interfaces' to make it a static network:

[pre]#​

auto eth0​

iface eth0 inet static​

address 192.168.254.254​

netmask 255.255.255.0​

#[/pre]​

For DHCP, edit /etc/dhcp/dhcpd.conf so the Basic-Talk can get an IP address and name server IP, the default gateway on the WiFi network:

[pre]#​

option domain-name-servers 192.168.0.1; # Found ad-hoc after connecting to WiFi​

option routers 192.168.254.254; # The gateway of the eth0 interface​

default-lease-time 36000; # A 10hr interval​

subnet 192.168.254.0 netmask 255.255.255.0 {​

range 192.168.254.240 192.168.254.253; # Just the upper region​

}​

#[/pre]​

There is only one iptable entry needed to make NAT work correctly:

[pre]#​

cd /etc/network/if-pre-up.d​

ls -alh iptables​

-rwxr-xr-x 1 root root 119 Jun 2 08:28 iptables​

cat iptables​

#!/bin/bash​

#​

# Created to make iptables entry for Talk-Basic​

#​

iptables -t nat -A POSTROUTING -o eth1 -j MASQUERADE​

#[/pre]​

We know from ad hoc observations that the WiFi interface is generated on eth1. This statement enables NAT to use the eth1 address as the 'alias' for all other network devices.

The last key is making sure IP forwarding (routing) is enabled:

[pre]#​

egrep ip_forward /etc/sysctl.conf​

net.ipv4.ip_forward=1[/pre]​

Like most things Linux, the descriptions found on the net frequently try to cover every option leaving one more confused than when starting. I wanted a minimalist approach even if specific to an IBM ThinkPad running Debian Linux. No need to 'go nuts' with a lot of wasted conditionals.

Bob Wilson

 

We are starting to see some abnormal network saturation events. I'm just starting the debug but for now, the ThinkPad is turned off until I can diagnose and come up with a fix.

There are network failure modes that can involve run-away error handling. The Voice-over-IP should be using UDP packets and there may be pathological modes involved. Regardless, it looks to be a 'learning experience.

Bob Wilson

 

Turns out the problem was the HotSpot location and the recently 'leafed' trees. Relocating it and service looks pretty good!

But in the meanwhile, found this puppy:

(Bestek Wireless Phone)

GSM compatible, it works great on T-Mobile. Just transfer the SIM card and voila, a desktop-style, cellphone. Just the thing for folks who want larger digits and 'no cords.' Got mine from Ebay for ~$35 and it looks to be a keeper.

Bob Wilson

 

Well I did meet her in 1977.

Bob Wilson