Linux box takes 10 seconds to make a connection

My machine is taking 10 seconds to establish a connection. Once the connection is established, it is up to speed and works correctly. But if I for example ping www.google.com, it takes 5 seconds for

PING www.l.google.com (72.14.247.147) 56(84) bytes of data.

to show up, and 5 more seconds for each

64 bytes from ag-in-f147.google.com (72.14.247.147): icmp_seq=1 ttl=243 time=100 ms

to show up.

My only clue is that I recently disconnected my computer from the Ethernet cable and rebooted it.

I use a static IP address and my router is configured correctly. My computer is the only one connected to the router that has this problem.

What configuration can I check to solve this problem?

DNS.

Make sure that your reverse DNS is working properly. You can verify this by typing "ping -n www.google.com". Immediate responses.