tcp settings

[Rob Sargent]

I'm wondering if there's a disconnect between my servers postgresql.conf 
and the system tcp settings? Are the config names supposed to match a 
file in /proc/sys/net/ipv4?

In postgres 14 install's postgresql.conf on centos 7:

   # - TCP settings -
   # see "man tcp" for details

   #tcp_keepalives_idle = 0                # TCP_KEEPIDLE, in seconds;
   # 0 selects the system default
   #tcp_keepalives_interval = 0            # TCP_KEEPINTVL, in seconds;
   # 0 selects the system default
   #tcp_keepalives_count = 0               # TCP_KEEPCNT;
   # 0 selects the system default
   #tcp_user_timeout = 0                   # TCP_USER_TIMEOUT, in
   milliseconds;
   # 0 selects the system default

   #client_connection_check_interval = 0   # time between checks for client
   # disconnection while running queries;
   # 0 for never

and in the /proc/sys/net/ipv4 I see no "keepalives" plural.

   tcp_abort_on_overflow tcp_fastopen_key           tcp_min_snd_mss
   tcp_slow_start_after_idle
   tcp_adv_win_scale                 tcp_fin_timeout
   tcp_min_tso_segs          tcp_stdurg
   tcp_allowed_congestion_control    tcp_frto tcp_moderate_rcvbuf      
   tcp_synack_retries
   tcp_app_win                       tcp_invalid_ratelimit
   tcp_mtu_probing           tcp_syncookies
   tcp_autocorking                   tcp_keepalive_intvl(75)
   tcp_no_metrics_save       tcp_syn_retries
   tcp_available_congestion_control  tcp_keepalive_probes(9)
   tcp_notsent_lowat         tcp_thin_dupack
   tcp_base_mss                      tcp_keepalive_time(7200)
   tcp_orphan_retries        tcp_thin_linear_timeouts
   tcp_challenge_ack_limit           tcp_limit_output_bytes
   tcp_reordering            tcp_timestamps
   tcp_congestion_control            tcp_low_latency
   tcp_retrans_collapse      tcp_tso_win_divisor
   tcp_dsack                         tcp_max_orphans
   tcp_retries1              tcp_tw_recycle
   tcp_early_retrans                 tcp_max_ssthresh
   tcp_retries2              tcp_tw_reuse
   tcp_ecn                           tcp_max_syn_backlog
   tcp_rfc1337               tcp_window_scaling
   tcp_fack                          tcp_max_tw_buckets
   tcp_rmem                  tcp_wmem
   tcp_fastopen                      tcp_mem tcp_sack                 
   tcp_workaround_signed_windows


My issue is that psql is timing out with "SSL SYSCALL error: Connection 
timed out".  The TCP defaults for keepalive look fine to me but not what 
I'm experiencing.  I have PGCONNECT_TIMEOUT=0 in my env for psql.