Hosted VoIP Firewall Requirements

Hosted VoIP Firewall Requirements

  • Firewall

Traffic to/from to the following IP Addresses must be permitted. 


Source IP Address
Source Port
Destination IP Addresses
Destination Ports
LAN Network or Voice VLAN
1023 - 65535

194.50.55.0/24
194.50.56.0/24
52.29.124.181
3.124.165.251
119.28.67.228
52.221.130.73
35.161.51.90
35.82.75.208
TCP 20 - 25
TCP 389
TCP/UDP 3478
TCP 80
TCP 443
TCP 8443
TCP 21050 - 21051
UDP 21059
UDP 5060
UDP 10000 - 20000
UDP 30000 - 50000

  • Web Filtering

Please add add the following URLs to the list of permitted destinations if your organisation uses a Web Filtering service. Please also exclude the following URLs from HTTPS inspection. (Also known as SSL inspection, TLS inspection, TLS break and inspect, and HTTPS interception)

*.sip2sip.net
rps.yealink.com
rpscloud.yealink.com
fdps.fanvil.com
gdms.cloud
fm.grandstream.com

  • DHCP

The preferred IP address assignment mechanism is DHCP as installations typically take less time to complete. Static address assignments are only used when absolutely necessary. Please also refer to the section relating to VLAN.

  • SIP ALG (Also known as SIP Transformations / SIP Helper / SIP Inspection)

SIP ALG must always be disabled on the sites router/firewall.


SIP Application Layer Gateway (SIP ALG) is common in many routers and in most cases enabled by default. Its primary use is to modify VoIP packets to aid NAT traversal. Active SIP ALG has been known to cause a plethora of problems caused by adjusting VoIP packets incorrectly, manifesting in a range of intermittent issues such as one way audio, dropped calls, problems transferring calls and handsets dropping registration.


For instructions on disabling SIP ALG, please refer to your router’s documentation.


B4BC will be unable to accept any faults or issues with its VoIP service if SIP ALG is enabled.

  • UDP NAT Session Timeout

Your VoIP Telephone performs a SIP registration every 600 seconds and will send a keep alive every 15 seconds. This is an outbound initiated connection utilising the UDP protocol. The purpose of the registration is to inform the ITSP how to route calls to the respective user agent.


Many routers terminate idle UDP sessions after only a few seconds.  The effect of this is that following SIP registration, inbound calls will only be successful for those first few seconds after registration. After this period, inbound calls will fail (Assuming the UDP connection has been idle) until the registration expires and the user agent re-registers. To avoid this scenario, UDP session timers should be set to a minimum of 180 seconds.

  • Quality of Service (QOS)

Quality of service (QOS) refers to the ability of your router to prioritize voice traffic (VoIP) differently than regular internet traffic on your network. VoIP is a real time protocol which means that if information is lost or delayed it will result in a noticeable drop in call quality.

  • Virtual LAN

We can accommodate VLANs if necessary. If your network has different subnets for various purposes, please let us know which network you would like us to use, or if you require the use of statically assigned IP Addresses.

We will need to know in advance which physical port to connect to in the case of port based VLANs, or any VLAN Tags which may be required for IEEE802.1Q type networks.


Disclaimer:

The information contained within in this document may change to keep abreast of current trends.  Best 4 Business Communications cannot accept responsibility for costs you may incur should it be necessary to modify your network as a result of an update to this information.

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