It looks like this:

[james@workstation ~]$  ping google.com
ping: unknown host google.com

[james@workstation ~]$  dig google.com +short
72.14.204.147
72.14.204.99
72.14.204.103
72.14.204.104

What ended up happening was that the VPN was configured to tunnel all traffic through it, so when it re-wrote the /etc/resolv.conf file, it didn’t append the VPN nameservers to the nameservers provided to us by our DHCP lease, but completely overwrote them. I’m assuming that when you closed the VPN it would replace the resolv.conf file with the one containing the non-VPN nameservers but since I killed it, it was not restored.

Anyway, the fix was easy but finding it out was annoying.

All you have to do is release and renew your DHCP lease.

You could try:

dhclient -r; dhclient

… but I was on an SSH connection and I didn’t quite trust the second command to be run after I lost the connection when the lease was released (this seems like a silly fear but whatever).

Instead I wrote a bash script and put it in a file:

#!/bin/bash
#refreshlease.sh
IFACE="eth0"

dhclient -r ${IFACE}
dhclient ${IFACE}

… and ran that over the SSH connection. The connection seemed to get dropped for a few seconds but then came back up. Checking /etc/resolv.conf showed that my original nameservers were, in fact, back and I was able to resolve DNS queries:

[james@workstation ~]$  ping google.com
PING google.com (64.233.169.105) 56(84) bytes of data.
64 bytes from yo-in-f105.1e100.net (64.233.169.105): icmp_seq=1 ttl=238 time=31.1 ms

Some notes:

• For a bandwidth tester we used iperf, a linux script that has been ported to windows via a cygwyn build.
  • For Linux we just ran “yum install iperf”
  • For Windows we googled “iperf windows”, but here is one binary from UCF.
• The real path just explains the connection between the two units.
• The window size was automatically determined by iperf.
• The 10 second test duration is iperf’s default.

And the same data graphically:

As you can see, there is considerable bandwidth improvement, even for the integrated NIC (and the PCI NIC is more than twice as fast as that!)

I have a quad-core AMD box (running Fedora 11), an AMD Phenom II X4 955 Black Edition box (running Windows 7), a few random head-less desktops, a laptop (F11) and a netbook (F11).

I run a fileserver on one box, I run an X session through ssh on my Windows box to access linux GUI stuff, I frequently transfer files between computers and I wanted to be able to access them by my defined hostname rather than the dynamic IP address my router assigned them (WRT54G running DD-WRT v24 SP1).

Now you may say, “dude, just give them static IP’s and be done with it.”  I considered that, but I would much rather remember “tophat” and “fractal” than 192.168.1.5 and 192.168.12.  Plus I’m a nerd and if there’s a way, I’ll figure it out.

… so I figured it out.

Windows will automatically report the Hostname of the computer (I think Windows calls it the Computer Name), so you won’t have to configure that.  You will however, have to allow your router to cache the hostnames and resolve them to IPs, and you will need to configure Linux to report the hostname when a DHCP lease is acquired.

Configure Router

1. Login to your router
2. Click on the “Services” tab
3. Under DNSMasq enable both options (“Enable DNSMasq” and “Enable Local DNS”)
4. Click “Apply Settings”

Configure Linux to Report Hostnames

1. Disclaimer: This is using Fedora 11 – other distros/versions may vary.
2. You should really pick a unique hostname per interface, so in the case that they’re both connected there isn’t a conflict.
3. As root, or with appropriate permissions, edit /etc/sysconfig/network-scripts/ifcfg-{interface} (ie /etc/sysconfig/network-scripts/ifcfg-eth0).
4. Add this line:

DHCP_HOSTNAME=fractal

1. Save the file
2. Restart the network service (sudo service restart network, or use the GUI)
3. Release your DHCP lease (sudo dhclient -r)
4. Renew your DHCP lease (sudo dhclient or ifconfig {interface} down; ifconfig {interface} up)

Configure Windows 7 to resolve hostnames (source)

1. Go into Network Connections (I just typed “Network Connections” om the start icon -> run box)
2. Right click on your Network Adapter and go into Properties
3. Select “Internet Protocol Version 4 (TCP/IPv4)”
4. Under the General Tab click Advanced
5. Under the DNS Tab select the radio button that says “Append these DNS suffixes (in order)”
6. Click “Add…”
7. Enter a single period in the text box and click “Add.”
8. Click OK in the “Advanced TCP/IP Settings” Dialog
9. Click OK in the “Local Area Connection Properties” Dialog

And there you go.