Problems communicating with docker container from host on default network

General
1

Unable to communicate to a container from the host on a random (unknown until runtime) port.

Suspect problem likely to lie in security / NAT rules of docker restricting access to containers. Currently learning how to work with iptables to enable the communication without messing up host network communication.

Working

  1. Ping between host and container.
  2. Ping between container to container.
  3. ssh from container to host
  4. dynamic port communication between containers on default network

Fails

  1. netcat listen on port in container; netcat port on host
  2. ssh from container on default network to hostuser@localhost (connection refused)

Types of Networks

  1. Default docker
  2. Custom docker bridge
  3. Linux bridge with assigned IP addresses
  4. Macvlan (can’t communicate with host as default behavior – not investigated very far)

TCP Dump with Netcat

tcpdump: listening on br0, link-type EN10MB (Ethernet), capture size 262144 bytes
2019-07-31 10:11:12.236156 IP (tos 0x0, ttl 64, id 15524, offset 0, flags [DF], proto TCP (6), length 60)
    10.0.190.0.56818 > 10.0.190.4.1234: Flags [S], cksum 0x9033 (incorrect -> 0xc062), seq 1635619556, win 29200, options [mss 1460,sackOK,TS val 2207296 ecr 0,nop,wscale 7], length 0
2019-07-31 10:11:12.236192 IP (tos 0x0, ttl 64, id 33639, offset 0, flags [DF], proto TCP (6), length 40)
    10.0.190.4.1234 > 10.0.190.0.56818: Flags [R.], cksum 0x48a4 (correct), seq 0, ack 1635619557, win 0, length 0
2019-07-31 10:11:17.241132 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 10.0.190.4 tell 10.0.190.0, length 28
2019-07-31 10:11:17.241153 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 10.0.190.0 tell 10.0.190.4, length 28
2019-07-31 10:11:17.241155 ARP, Ethernet (len 6), IPv4 (len 4), Reply 10.0.190.0 is-at 86:86:c3:9e:6a:93, length 28
2019-07-31 10:11:17.241157 ARP, Ethernet (len 6), IPv4 (len 4), Reply 10.0.190.4 is-at 02:42:0a:00:be:04, length 28

Any help would be appreciated.