TCP Tuneable Parameters

Question

Hi,
I'd like to know if there are parameters in Solaris to control the following TCP options; I looked in the "Solaris Tunable Parameters Reference Manual" but didn't find the ones I need, perhaps they're undocumented. I'm mostly interested in parameters that can be set on a kernel-wide basis (using "ndd", for example), not a per-socket basis.
1) Turn on/off the Fast Retransmit - Fast Recovery algorithm.
2) Turn on/off the Nagle algorithm.
3) Set the persist timer value (also referred to as persistence timeout).
4) Turn on/off Karn's algorithm. Is this algorithm supported in Solaris?
5) Turn on/off the Protection Against Wrapped Sequence Numbers (PAWS) algorithm. Is this algorithm supported in Solaris?
Many thanks,
Nick

Answer 1

Hi,
Here's the list of TCP tunables that you can modify using ndd:
# ndd -get /dev/tcp \?
? (read only)
tcp_time_wait_interval (read and write)
tcp_conn_req_max_q (read and write)
tcp_conn_req_max_q0 (read and write)
tcp_conn_req_min (read and write)
tcp_conn_grace_period (read and write)
tcp_cwnd_max (read and write)
tcp_debug (read and write)
tcp_smallest_nonpriv_port (read and write)
tcp_ip_abort_cinterval (read and write)
tcp_ip_abort_linterval (read and write)
tcp_ip_abort_interval (read and write)
tcp_ip_notify_cinterval (read and write)
tcp_ip_notify_interval (read and write)
tcp_ipv4_ttl (read and write)
tcp_keepalive_interval (read and write)
tcp_maxpsz_multiplier (read and write)
tcp_mss_def_ipv4 (read and write)
tcp_mss_max_ipv4 (read and write)
tcp_mss_min (read and write)
tcp_naglim_def (read and write)
tcp_rexmit_interval_initial (read and write)
tcp_rexmit_interval_max (read and write)
tcp_rexmit_interval_min (read and write)
tcp_deferred_ack_interval (read and write)
tcp_snd_lowat_fraction (read and write)
tcp_sth_rcv_hiwat (read and write)
tcp_sth_rcv_lowat (read and write)
tcp_dupack_fast_retransmit (read and write)
tcp_ignore_path_mtu (read and write)
tcp_rcv_push_wait (read and write)
tcp_smallest_anon_port (read and write)
tcp_largest_anon_port (read and write)
tcp_xmit_hiwat (read and write)
tcp_xmit_lowat (read and write)
tcp_recv_hiwat (read and write)
tcp_recv_hiwat_minmss (read and write)
tcp_fin_wait_2_flush_interval (read and write)
tcp_co_min (read and write)
tcp_max_buf (read and write)
tcp_strong_iss (read and write)
tcp_rtt_updates (read and write)
tcp_wscale_always (read and write)
tcp_tstamp_always (read and write)
tcp_tstamp_if_wscale (read and write)
tcp_rexmit_interval_extra (read and write)
tcp_deferred_acks_max (read and write)
tcp_slow_start_after_idle (read and write)
tcp_slow_start_initial (read and write)
tcp_co_timer_interval (read and write)
tcp_sack_permitted (read and write)
tcp_trace (read and write)
tcp_compression_enabled (read and write)
tcp_ipv6_hoplimit (read and write)
tcp_mss_def_ipv6 (read and write)
tcp_mss_max_ipv6 (read and write)
tcp_rev_src_routes (read and write)
tcp_wroff_xtra (read and write)
tcp_extra_priv_ports (read only)
tcp_extra_priv_ports_add (write only)
tcp_extra_priv_ports_del (write only)
tcp_status (read only)
tcp_bind_hash (read only)
tcp_listen_hash (read only)
tcp_conn_hash (read only)
tcp_acceptor_hash (read only)
tcp_host_param (read and write)
tcp_time_wait_stats (read only)
tcp_host_param_ipv6 (read and write)
tcp_1948_phrase (write only)
tcp_close_wait_interval(obsoleted- use tcp_time_wait_interval) (no read or write)
Regards,
--Sun/DTS