No SYNACK to port 80?

["st.john.johnson@gmail.com" <st.john.johnson@gmail.com>]

Hi there.  I'm having a strange problem.  Sometimes, for short periods
of time, when connecting to my web server from an external IP address,
the connection doesn't complete.  But at the same time, I can connect
from a local ip address.

I ran tshark on the machine to monitor traffic when these "short
periods" happen and I noticed that for external connections, my
machine is not replying to the ACK in the three-way handshake.

  0.000000 69.120.132.213 -> 10.1.1.202   TCP 52197 > www [SYN] Seq=0
Len=0 MSS=1460 WS=2
  3.006786 69.120.132.213 -> 10.1.1.202   TCP 52197 > www [SYN] Seq=0
Len=0 MSS=1460 WS=2
  8.973167 69.120.132.213 -> 10.1.1.202   TCP 52197 > www [SYN] Seq=0
Len=0 MSS=1460

I don't have iptables installed, and SELinux is not enabled.