Nat Traversal - Snom m9 DECT Administrator's Manual

Netmask: This is the netmask for the network, if DHCP is switched off.
IP Gateway: This is the default gateway of the network, if DHCP is switched off.
DNS Server: Multiple DNS servers can be used for DNS redundancy. If one of them fails, a backup
will be available.
DNS Domain: This is the DNS domain of the device, if DHCP is switched off.
NTP Server: NTP Time Server IP Address of hostname.
VLAN/ID: VLAN ID is the identification of the VLAN, which is basically used by the standard 802.1Q.
It has 12 bits and allows the identification of 4096 VLANs. Possible values range from 0 to 4095.
VLAN Priority: VLAN Priority lets the user assign a priority to outbound packets containing the speci-
fied VLAN-ID (VID). Possible values range from 0 to 7.
Provisioning Server: This field takes an auto configuration URL (links to a configuration XML file)
Settings refresh timer: This field indicates the number of seconds after which the m9 will refresh its
settings from the setting server periodically (0 = don't refresh).
SIP client port: Allows the m9 to bind the device to a fixed SIP UDP port (e.g., 5060). By default, the
m9 selects a random UDP port for SIP signaling.
RTP Type of Service (ToS/Diffserv): Enables the m9 to support quality of service (QoS) for RTP traf-
fic in the network via Diffserv.
SIP Type of Service (ToS/Diffserv): Enables the m9 to support quality of service (QoS) for SIP traffic
in the network via Diffserv.
Allow Check-Sync: Allows reboot/re-sync with SIP NOTIFY.
STUN server: STUN (Simple Traversal of UDP through NAT) server and port.
STUN refresh interval in seconds: Interval for STUN refresh.

NAT Traversal

NAT is typically used by a router or firewall to allow devices that are on a LAN (Local Area Network) and have
private IP addresses to share a single, public IP address. To maintain the session, the NAT'ed snom m9 behind
the firewall must keep sending messages to keep the session open. These messages are called "NAT Keep
Alive" messages. The snom m9 provides the following provisionable settings for NAT Keep Alive:
outbound_method: crlf or stun
outbound_tcp: Refresh interval in seconds for TCP connections (default is 60)
outbound_udp: Refresh interval in seconds for UDP connections (default is 20)
Network Settings
17