Which IPs should I whitelist in my firewall?

If you use a firewall that limits access from and/or to certain IPs, please whitelist the IP ranges listed below for both TCP and UDP.

Subnet	Start IP	End IP
185.19.236.0/22	185.19.236.0	185.19.239.255
Service	Port number
SIP	5060 UDP     5060 TCP     5061 TLS
RTP	ANY PORT - UDP
Provisioning	https://dm.yealink.com   https://api-dm.yealink.com   https://rps.yealink.com   52.71.103.102   35.156.148.166   106.15.89.161   47.75.58.202   47.89.187.0   80 TCP     80 TLS     443 TCP     443 TLS   443 UDP
Fonzer C2D	94.237.41.99

Do not forget: Disable SIP Application Layer Gateway (SIP ALG).

One last thing to check in the firewall is to allow fragmented packets. If we send packets of more than 1500 bytes, they will be sent in a fragmented way. Not all firewalls allow fragmented packets and this should also be checked.

• Disable SPI (Stateful Packet Inspection).
• Disable Strict Security in the Firewall options.