Evan Chu: Linux Tips and Hints

Evan Chu

Linux Tips and Hints

Hints for Verizon's Westell router

These hints apply to Verizon's Westell DSL router (model E90-610015-06, Revision L). It is a TCP/IP router; not an ethernet bridge nor an ethernet hub. It has a firewall, a DHCP server, and a DNS server. All are configurable by browsing to the default URL of http://192.168.1.1/. The user name is admin, the default password is "password".

The Westell router can be used as a home network router. In this usage scenario, an ethernet hub connects to the Westell router. Then the hub connects all the home computers. The Westell router's firewall, DNS server, and DHCP server must be configured normally.

For an alternate usage scenario, the Westell router can be used an ethernet-to-DSL bridge. The Westell "bridge" connects to a home network router, such as a Linksys router. This is my current configuration. I want my Linksys router to be fully exposed to the internet.

The Westell "bridge's" DMZ host must be configured as the MAC address of the Linksys router. The DMZ host is fully exposed to the internet. The Westell "bridge's" firewall must be disabled, because the Linksys router provides the firewall.

Setup Verizon DSL service

I subscribe to Verizon DSL service. Verizon sent me a Westell router, model E90-610015-06, Revision L. At the front of the router, there is the word "Model 6100." In its default configuration, it captures all HTTP requests and redirects them to Verizon's sign up page. The page wants the user to download and install Verizon's software to complete the installation. I use Linux so that software is not going to work for me.

Here is how to circumvent it. Browse to
http://192.168.1.1/verizon/redirect.htm
The default user name and password are: admin, password. Click the "disable" button to stop the HTTP redirect.

Now try to connect to Google using a browser. If all goes well, you should be successful. If the browser fails to connect to any web site on the internet, then further router configuration is needed. In this situation, the most likely problem is the user name and password for the router is not correct.

Browse to 192.168.1.1, which is the router's home page. Study the "My Modem" column. The "DSL link" should indicate connected. The "internet status" may indicate disconnected. The "IP address" may indicate "PPP down". The above evidence indicates a wrong user name or password for the router.

Call Verizon's technical support to request a temporary user name and password. Enter them into the router, so it can establish a PPP connection to Verizon. Then browse to www.verizon.net, to create a new personally-unique user name and password. Also create a security question and answer. Enter the personally-unique user name and password into the router to replace the temporary ones. Restart the router. If all goes well, you should be successful.

Many Verizon agents transfered my call because I told them I use Linux. Eventually and luckily, an agent took my call and spent 20 minutes helping me.

Basic Samba diagnostics

I have been participating in the Ubuntu Forums to help people with their networking problems related to sharing files between Windows and Linux. Samba is the software package in Linux that allows sharing files between Windows and Linux.

I wrote a simple script, samba-net-diag1, that collects some basic diagnostic information about a Linux system's Samba capabilities. This information can help further diagnosis.

Windows serves files to Linux

A Windows Vista computer must be configured to serve files to a Linux computer over a local area network.

Turn on file sharing

Go to "Network" and turn on "file sharing" and turn off "password protected sharing."
Go to "Control Panel; User Accounts" and turn on guest account. Set an empty password.

Adjust shared folder properties

Go to the directory to be shared and adjust its advanced sharing properties.
In the "share permissions;" Everyone allows read; Guest allows read.

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A Linux user uses tools from the Samba package to access files on a Windows computer. Use the shell script, netuse, to connect to a Windows machine on the network. Use the shell script, netview, to list the available shared folders on a Windows computer.

The Linux automounter can be configured to automatically mount a Windows shared folder. Edit the /etc/auto.misc and add:

echome3  -fstype=smbfs,username=dummy,password=dummy  ://echome3/box

In the above line, //echome3/box is the shared folder (box) on the Windows machine (echome3).

Launch Nedit

Nedit is a very compact and fast text editor that runs on a variety of Unix and Linux distributions. I use the following startup script to launch the editor. The script automatically launches Nedit into the background.

#!/bin/bash
# $@ expands to all positional parameters
NeditPath=$HOME/local/nedit5.5
$NeditPath/nc -svrcmd "$NeditPath/nedit -server" -group $@ &> /dev/null &

Linux serves files to Windows

On a Linux computer, I use the tools in the Samba package to serve files to Windows computers over a local area network. Configure the Samba server using the configuration file, /etc/samba/smb.conf:

[global]
workgroup = workgroup
server string = echome2; Ubuntu
security = share
wins server = 10.2.99.238   10.0.8.238
time server = yes

[box]
comment = my read-only share
path = /mnt/box
read only = yes
guest ok = yes

[boxpriv]
comment = private writeable share
path = /mnt/box
read only = no
guest ok = no
username = evanchu

The username, evanchu, must be added to the smbpasswd file using the smbpasswd command. Evanchu must also exist in the Linux passwd file. On a Windows Vista computer, go to "Network." It should automatically discover the Linux computer.

Network Time Protocol

Use the following command to set the clock immediately:
ntpdate -v pool.ntp.org

Edit /etc/ntp.conf to change the "server" option. Set "server" to a public NTP server's hostname. I use pool.ntp.org.

Set the time-zone environment variable to TZ=EST5DST, which indicates U.S.A. Eastern Standard Time (+5 hours from Universal Coordinated Time) and Daylight Saving Time is in effect.

Firewall and network-address-translate with iptables

Use the myfirewall shell script to:

Clear all chains in the iptables.
Setup network-address-translation so multiple hosts on the internal network can share one public IP address on the ppp0 interface.
Setup a basic firewall to protect the internal network.

Less

Put the global configuration for less, the opposite of more, as an environment variable: export LESS="-F -w -X"

Automount file systems

I configure the automount daemon with two configuration files: /etc/auto.master and /etc/auto.misc. The example shows how to automount cd, floppy, and Samba file systems.