Description of problem:
Our mailserver has been sending oversized packets since mid morining.  No notice is take of the MTU of 1500 on eth0, we have been getting packet up to 20k !!

Version-Release number of selected component (if applicable):
2.6.35.12-88.fc14.i686

How reproducible:
As I don't know the cause, I can't say but it is happening  a lot.

Steps to Reproduce:
1.
2.
3.
  
Actual results:
18:22:46.036994 IP agree-31.godzone.net.nz.pop3 > mail-fx0-f2.google.com.37569: Flags [.], seq 95273:110009, ack 49, win 20, options [nop,nop,TS val 7499779 ecr 612154545], length 14736

---- 14736 !!

18:22:46.039555 IP mail-fx0-f2.google.com.37569 > agree-31.godzone.net.nz.pop3: Flags [.], ack 70713, win 1002, options [nop,nop,TS val 612154547 ecr 7499394], length 0
18:22:46.039570 IP mail-fx0-f2.google.com.37569 > agree-31.godzone.net.nz.pop3: Flags [.], ack 73169, win 1002, options [nop,nop,TS val 612154547 ecr 7499396], length 0
18:22:46.040291 IP mail-fx0-f2.google.com.37569 > agree-31.godzone.net.nz.pop3: Flags [.], ack 75625, win 1024, options [nop,nop,TS val 612154547 ecr 7499396], length 0
18:22:46.041092 IP mail-fx0-f2.google.com.37569 > agree-31.godzone.net.nz.pop3: Flags [.], ack 78081, win 1024, options [nop,nop,TS val 612154548 ecr 7499396], length 0
18:22:46.041104 IP mail-fx0-f2.google.com.37569 > agree-31.godzone.net.nz.pop3: Flags [.], ack 80537, win 1024, options [nop,nop,TS val 612154549 ecr 7499396], length 0
18:22:46.041120 IP agree-31.godzone.net.nz.pop3 > mail-fx0-f2.google.com.37569: Flags [.], seq 110009:118605, ack 49, win 20, options [nop,nop,TS val 7499783 ecr 612154549], length 8596

---- 8596 !!

18:22:46.041142 IP agree-31.godzone.net.nz.pop3 > mail-fx0-f2.google.com.37569: Flags [P.], seq 118605:119758, ack 49, win 20, options [nop,nop,TS val 7499783 ecr 612154549], length 1153
18:22:46.041591 IP mail-fx0-f2.google.com.37569 > agree-31.godzone.net.nz.pop3: Flags [.], ack 82993, win 1024, o

Expected results:

Certainly not packets of length greater than the MTU, which we dropped to see if it would help.

eth0      Link encap:Ethernet  HWaddr 00:0C:29:8A:53:01  
          inet addr:192.138.251.31  Bcast:192.138.251.127  Mask:255.255.255.128
          inet6 addr: 2001:df0:dc::251:31/64 Scope:Global
          inet6 addr: fe80::20c:29ff:fe8a:5301/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1280  Metric:1
          RX packets:1704615 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1602035 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:2174572162 (2.0 GiB)  TX bytes:842868785 (803.8 MiB)



Additional info:

The server has been rebooted multiple time.  It is a VM running on ESXi 4.0 and is using the e1000 driver.  Started with pcnet32 but that has the issue as well.
We currently have net.ipv4.ip_pmtu_disc set to 1.