All core NFs (include NRF) register refused/can't be up when other Core NFs and UPF are running on different server (physical machine)

Dear 5GC team,
My UPF is running on a separate ubuntu 1804 (desktop server), with IP 192.168.5.53; and all other core NFs (except n3iwf, there is no n3iwf running) are running on another ubuntu 1804 (desktop server), with IP 192.168.2.52).

on machine 192.168.5.52, in free5gc/config folder, for every *.conf file, I change ‘127.0.0.1’ and localhost to ‘192.168.5.52’, also in ‘free5gc.conf’, I change ‘127.0.0.1’/localhost to ‘192.168.5.52’.
I also changed ‘127.0.0.1:27017’ to ‘192.168.5.52:27017’ in below two files:

./sample/ran_attach_config/nrfcfg.conf: MongoDBUrl: “mongodb://127.0.0.1:27017”
./src/test/ngsetup_test.go: MongoDBLibrary.SetMongoDB(“free5gc”, “mongodb://127.0.0.1:27017”)

and below are my upf and smf config:

~/free5gc/src/upf/build/config/upfcfg.yaml :

info:
  version: 1.0.0
  description: UPF configuration

configuration:
  # debugLevel: panic|fatal|error|warn|info|debug|trace
  debugLevel: info

  pfcp:
    - addr: 192.168.5.53

  gtpu:
    - addr: 192.168.5.55
    

  apn_list:
    - apn: internet
      cidr: 60.60.0.0/24  

~/free5gc/config/smfcfg.conf :

pfcp:
    addr: 192.168.5.52
  userplane_information:
    up_nodes:
      gNB1:
        type: AN
        an_ip: 192.188.2.3
      UPF:
        type: UPF
        node_id: 1921.168.5.53
        up_resource_ip: 192.188.2.2

    links:
      - A: gNB1
        B: UPF
  ue_subnet: 60.60.0.0/16
  nrfUri: http://localhost:29510

UPF is successfully init and running on machine with IP 192.168.5.53; on machine with IP 192.168.5.52, NRF and all other core NFs register are refused, with below error:

SMF:
NFO[2020-09-08T00:00:52-07:00]/src/smf/consumer/nnrf.go:40 free5gc/src/smf/consumer.SendNFRegistration() SMF register to NRF Error[Put “http://192.168.5.52:29510/nnrf-nfm/v1/nf-instances/61b24f16-5d85-406e-b080-b11f747d4522”: unexpected EOF] SMF=app
127.0.0.1:27017UDM register to NRF Error[Put “http://192.168.5.52:29510/nnrf-nfm/v1/nf-instances/53b42c1d-e067-45d7-b21d-b11ee1067de6”: dial tcp 192.168.5.52:29510: connect: connection refused]
INFO[2020-09-08T00:00:54-07:00]/src/smf/consumer/nnrf.go:40 free5gc/src/smf/consumer.SendNFRegistration() SMF register to NRF Error[Put “http://192.168.5.52:29510/nnrf-nfm/v1/nf-instances/61b24f16-5d85-406e-b080-b11f747d4522”: dial tcp 192.168.5.52:29510: connect: connection refused] SMF=app
UDM register to NRF Error[Put “http://192.168.5.52:29510/nnrf-nfm/v1/nf-instances/53b42c1d-e067-45d7-b21d-b11ee1067de6”: dial tcp 192.168.5.52:29510: connect: connection refused]
INFO[2020-09-08T00:00:56-07:00]/src/smf/consumer/nnrf.go:40 free5gc/src/smf/consumer.SendNFRegistration() SMF register to NRF Error[Put “http://192.168.5.52:29510/nnrf-nfm/v1/nf-instances/61b24f16-5d85-406e-b080-b11f747d4522”: dial tcp 192.168.5.52:29510: connect: connection refused] SMF=app
UDM register to NRF Error[Put “http://192.168.5.52:29510/nnrf-nfm/v1/nf-instances/53b42c1d-e067-45d7-b21d-b11ee1067de6”: dial tcp 192.168.5.52:29510: connect: connection refused]
INFO[2020-09-08T00:00:58-07:00]/src/smf/consumer/nnrf.go:40 free5gc/src/smf/consumer.SendNFRegistration() SMF register to NRF Error[Put “http://192.168.5.52:29510/nnrf-nfm/v1/nf-instances/61b24f16-5d85-406e-b080-b11f747d4522”: dial tcp 192.168.5.52:29510: connect: connection refused] SMF=app
’ .
./log/free5gc.log:time=“2020-09-02T09:46:45-07:00” level=fatal msg=“server selection error: server selection timeout\ncurrent topology: Type: Unknown\nServers:\nAddr: 127.0.0.1:27017, Type: Unknown, State: Connected, Average RTT: 0, Last error: dial tcp 127.0.0.1:27017: connect: connection refused\n” func=free5gc/lib/MongoDBLibrary.RestfulAPIGetMany file="/home/andrew/free5gc/lib/MongoDBLibrary/api_mongoDB.go:53" MongoDB=MongoDB
./log/lib/mongodb_library.log:time=“2020-09-02T09:46:45-07:00” level=fatal msg=“server selection error: server selection timeout\ncurrent topology: Type: Unknown\nServers:\nAddr: 127.0.0.1:27017, Type: Unknown, State: Connected, Average RTT: 0, Last error: dial tcp 127.0.0.1:27017: connect: connection refused\n” func=free5gc/lib/MongoDBLibrary.RestfulAPIGetMany file="/home/andrew/free5gc/lib/MongoDBLibrary/api_mongoDB.go:53" MongoDB=MongoDB
UDM register to NRF Error[Put “http://192.168.5.52:29510/nnrf-nfm/v1/nf-instances/53b42c1d-e067-45d7-b21d-b11ee1067de6”: dial tcp 192.168.5.52:29510: connect: connection refused]

Looks like there is some server selection error, the system still think it’s 127.0.0.1.

Pls close this issue, it’s solved. thanks.