Page 389 - Asterisk™: The Future of Telephony

defaultip (peer)
The defaultip setting complements host=dynamic. If a host has not yet registered
with your server, you’ll attempt to send messages to the default IP address config-
ured here:

defaultip=192.168.1.101
deny (both)
Specific IP addresses and ranges can be controlled with the deny option. To restrict
access from a range of IP addresses, use a subnet mask—for example,
deny=192.168.1.0/255.255.255.0. You can also deny all addresses with
deny=0.0.0.0/0.0.0.0 and then allow only certain addresses with the permit com-
mand. Be aware of the security implications of this setting (see also permit):

deny=0.0.0.0/0.0.0.0
disallow (both)
See allow.
dtmfmode (both)
You can set dtmfmode to inband, rfc2833, or info. DTMF digits can be sent either
in band (as part of the audio stream), or out of band (as signaling information),
using the RFC 2833 or INFO methods. The inband method works reliably only
when using an uncompressed codec such as G.711, μlaw, or alaw. The recom-
mended method is to use rfc2833; however, some devices—such as those by
Grandstream—support the info method:
dtmfmode=rfc2833

In Asterisk 1.4, Variable Length DTMF was introduced in order to
allow Asterisk to correctly signal to the far end the duration of a
key press on the phone connected to the incoming channel (per
IETF RFC 2833). Older Asterisk systems do not understand the
variable-length parameter. In older Asterisk systems, DTMF deliv-
ered via RFC 2833 may not be correctly interpreted, leading to
strange effects in sessions such as voicemail. If you want to have
the older (pre-1.4) behaviour of the rfc2833 setting, you must add
the rfc2833compensate=yes option to the peer in sip.conf that de-
fines communication with your pre-1.4 Asterisk system.

fromdomain (peer)
This allows you to set the domain in the From: field of the SIP header. It may be
required by some providers for authentication:
fromdomain=my.hostname.tld
fromuser (peer)
This allows you to set the username with which to authenticate. The name con-
tained within the square brackets of the channel definition is usually used, but this

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