FreeBSD NFS server not responding to TCP SYN packets from Linux/SunOS clients

[Jim Rees]

  ps: It would be nice if someone with the right expertise could explore
      other things in TCP specifically for NFS. For example, I don't see
      why a retransmit timeout should go above about 100msec

nfs/rpc shouldn't retransmit at all over tcp except when there has been a
reconnect.  Tcp might retransmit, but modern implementations will always
choose the right timeout dynamically, unless packet loss is excessive.