Ubuntu Karmic - Net connection unusually laggy

Question

I've just installed Ubuntu 9.10 and fired up Firefox, what I have noticed is that the Internet is slower than it is with the other machines that I have with identical connection.

In particular, it takes it a long time for it to look up a server. Once downloading has begun, the speeds are normal, but it is very very laggy prior to starting the download: Firefox's status bar reports Looking up <server>... for up to 15 seconds, where it would usually just flicker for a fraction of a second.

Any ideas on what could be causing this and suggested fixes?

Thanks!

Answer 1

This could be an issue with the DNS-Servers. Try to set or change the default DNS-Servers to f.e. the OpenDNS ones. For a nice how-to please see the OpenDNS guide on how to change the DNS on Ubuntu.

Also, you could try SpeedTest for testing your connection a little further.

Answer 2

Check the DNS nameservers specified in /etc/resolv.conf. See that they match your other systems (ipconfig /dns or ipconfig /all for Windows from memory) or whatever is recommended by your ISP.

In a home network environment (and many office networks) the DNS servers are typically specified in the DHCP response that provides the IP address to your system if you use dynamic IP addressing. Sometime if there is a problem initalizing the connection, the DHCP client, dhclient or dhclient3 (from memory) may not of modified the DNS resolver file (/etc/resolv.conf). Quitting dhclient (dhclient -q I think) and doing ifdown ethX and then ifup ethX where ethX is replaced by your actually network device (eth0 for first Ethernet port, may be wlan0 or similiar for wireless) may fix the problem for you.

You can test use nslookup or dig to test a particular nameserver:

nslookup superuser.com dns1.example.net
dig stackoverflow.com @dns2.example.net

where dns#.example.net are the nameservers (DNS resolvers) you want to test.

Answer 3

To extend Bobby's comment about using OpenDNS. Here is how to set the DNS to OpenDNS:

1) right click on the network panel icon.

2) Choose Network Connections

3) Go to the connection you want to change the DNS Server of.

4) There should be a dropdown. Click it and choose "DHCP (Addresses Only)

5) There should be a text box labeled DNS Server. Type this in it: "208.67.222.222, 208.67.220.220" (without the quotes)

6) Click apply and close the network connections window.

Hope this helps!