length of captured packets more than MTU

I m running iperf between two machines (linux) and I can observe the mtu of both the interface开发者_StackOverflow中文版s connected is 1500.

I ran tcpdump to capture packets and I observed some packets have "length as 2962"....how come this is possible with mtu as only 1500?

Please clarify. Thanks!

Note: flags field is set as DF. and proto is TCP

Turning off gso (in linux) did the trick

Referred: http://lists.openwall.net/netdev/2008/11/14/20