Solaris 8 (and Previous Versions)

   Disable PMTUD:

$ ndd -set /dev/ip ip_path_mtu_discovery 0

   Set Maximum MSS to 1460:

$ ndd -set /dev/tcp tcp_mss_max 1460

   Source: The TCP/IP Illustrated: The Protocols, Vol. 1, Appendix E, by
   W. Richard Stevens and Gary R. Wright.


btw: Linux
echo 1 > /proc/sys/net/ipv4/ip_no_pmtu_disc