incomplete startup packet messages in logs

Hi Team,

I know this is has been answered a lot on the internet wrt ignoring,
but i am unable to figure out why I get these messages in logs
"incomplete startup packet"

I have a server running postgresql 10.5 on ubuntu16.04

i do not have any active external connections other than streaming
postgres replication.

postgres 7757 1 0 12:20 ? 00:00:00
/usr/lib/postgresql/10/bin/postgres -D /var/lib/postgresql/10/main -c
config_file=/etc/postgresql/10/main/postgresql.conf

postgres 7759 7757 0 12:20 ? 00:00:00 postgres: 10/main:
checkpointer process

postgres 7760 7757 0 12:20 ? 00:00:00 postgres: 10/main:
writer process

postgres 7761 7757 0 12:20 ? 00:00:00 postgres: 10/main: wal
writer process

postgres 7762 7757 0 12:20 ? 00:00:00 postgres: 10/main:
autovacuum launcher process

postgres 7763 7757 0 12:20 ? 00:00:00 postgres: 10/main:
archiver process

postgres 7764 7757 0 12:20 ? 00:00:00 postgres: 10/main:
stats collector process

postgres 7765 7757 0 12:20 ? 00:00:00 postgres: 10/main:
bgworker: logical replication launcher

postgres 7779 7757 0 12:20 ? 00:00:00 postgres: 10/main: wal
sender process replicator x.x.x.x(47792) streaming 3/FA0001B0

postgres 7780 7757 0 12:20 ? 00:00:00 postgres: 10/main: wal
sender process replicator x.x.x.x(50526) streaming 3/FA0001B0

postgres 7786 7757 0 12:21 ? 00:00:00 postgres: 10/main: wal
sender process barman_streaming x.x.x.x(43566) streaming 3/FA0001B0

also,

postgres=# select backend_type, query from pg_stat_activity;

backend_type | query

---------------------+---------------------------------------------------

autovacuum launcher |

background worker |

walsender |

walsender |

walsender |

client backend | select backend_type, query from pg_stat_activity;

background writer |

checkpointer |

walwriter |

but i still see

tail -1000 /var/log/postgresql/postgresql-10-main.log| grep
'incomplete startup packet'

2018-11-01 13:04:18 UTC LOG: incomplete startup packet

2018-11-01 13:08:18 UTC LOG: incomplete startup packet

2018-11-01 13:12:18 UTC LOG: incomplete startup packet

Note: exactly at 4 min interval.

i do not know C, but i tried to understand something from
https://github.com/postgres/postgres/blob/197e4af9d5da180190a0f2be851b095dba57d9cd/src/backend/postmaster/postmaster.c#L1891

without any active connections, i would rule any driver issue out.

i do not have ssl enabled, but not using it. I tried disabling it too.

postgres=# show ssl;

ssl

-----

off

(1 row)

I do not know, why those log messages are then showing up.

not errors in

ens160 Link encap:Ethernet HWaddr 00:50:56:a4:53:b6

inet addr:x.x.x.x Bcast:x.x.x.x Mask:x.x.x.x

inet6 addr: xxxxx/64 Scope:Link

UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1

RX packets:45403371 errors:0 dropped:0 overruns:0 frame:0

TX packets:8834699 errors:0 dropped:0 overruns:0 carrier:0

collisions:0 txqueuelen:1000

RX bytes:6417380742 (6.4 GB) TX bytes:56209193635 (56.2 GB)

lo Link encap:Local Loopback

inet addr:127.0.0.1 Mask:255.0.0.0

inet6 addr: ::1/128 Scope:Host

UP LOOPBACK RUNNING MTU:65536 Metric:1

RX packets:28985185 errors:0 dropped:0 overruns:0 frame:0

TX packets:28985185 errors:0 dropped:0 overruns:0 carrier:0

collisions:0 txqueuelen:1

RX bytes:7078785550 (7.0 GB) TX bytes:7078785550 (7.0 GB)

Regards,
Vijay