Flexisip Server on VirtualBox

[Emil Suleymanli]

Hello,

I am trying to set up Flexisip with minimal configuration on Ubuntu 18.04 on VirtualBox.
VirtualBox VM has 2 network adapters (NAT and Host-Only). Minimal configuration reference: https://wiki.linphone.org/xwiki/wiki/public/view/Flexisip/HOWTOs/Minimal%20registrar%20with%20authentication/  

I have successfully installed Flexisip, and flexisip-proxy service is running. But I am not able to connect from Linphone while being on the same network. 

systemctl status flexisip-proxy output:
● flexisip-proxy.service - Flexisip proxy server
   Loaded: loaded (/lib/systemd/system/flexisip-proxy.service; disabled; vendor preset: enabled)
   Active: active (running) since Sun 2020-08-09 18:06:00 EDT; 6s ago
     Docs: http://www.linphone.org/technical-corner/flexisip/overview
  Process: 3620 ExecStart=/opt/belledonne-communications/bin/flexisip --server proxy --daemon --syslog --pidfile /var/run/flexisip-proxy.pid (code=exited, status=0/SUCCESS)
 Main PID: 3621 (flexisip)
    Tasks: 6 (limit: 4666)
   CGroup: /system.slice/flexisip-proxy.service
           ├─3621 /opt/belledonne-communications/bin/flexisip --server proxy --daemon --syslog --pidfile /var/run/flexisip-proxy.pid
           └─3622 /opt/belledonne-communications/bin/flexisip --server proxy --daemon --syslog --pidfile /var/run/flexisip-proxy.pid

Aug 09 18:05:59 linux systemd[1]: Starting Flexisip proxy server...
Aug 09 18:05:59 linux flexisip[3620]: 2020-08-09 18:05:59:967 bctbx-error-[LAUNCHER] Watchdog PID: 3621
Aug 09 18:05:59 linux flexisip[3622]: Writing logs in : /var/opt/belledonne-communications/log/flexisip/flexisip-proxy.log
Aug 09 18:06:00 linux flexisip[3622]: DoSProtection: '/sbin/iptables -w -F FLEXISIP 2>&1' failed with output 'iptables: No chain/target/match by that name.
                                      '.
Aug 09 18:06:00 linux flexisip[3622]: DoSProtection: '/sbin/ip6tables -w -F FLEXISIP 2>&1' failed with output 'ip6tables: No chain/target/match by that name.
                                      '.
Aug 09 18:06:00 linux flexisip[3622]: Cannot open domain registration configuration file '/etc/flexisip/domain-registrations.conf'
Aug 09 18:06:00 linux systemd[1]: Started Flexisip proxy server.

flexisip.conf file:
[global]
aliases=localhost sip. example.org
default-servers=proxy presence
transports=sip:*

[stun-server]
enabled=true
bind-address=0.0.0.0
port=3478


[module::Registrar]
enabled=true
reg-domains=localhost
db-implementation=internal

[module::Authentication]
enabled=true
auth-domains=localhost
db-implementation=file
datasource=/etc/flexisip/users.db.txt


I have tried different values for transports section in global module; with and without stun-server module. 

In  users.db.txt file, I have tried the IP and sip.example.org for the domain part. 
All TCP/UDP connections are allowed. 

However, I am still not able to connect from Linphone on the same network.