[Asterisk-Users] Dynamic DNS causes problems

[Larry Hendrickson]

Hi all,

This is my first post to this list, so I apologize if it is a newbie
question.  I did quite a bit of reading and a number of Google searches
for answers and found people with dynamic DNS problems, but not the
same one.

I just recently set up Asterisk as a pbx system for my home using
Broadvoice.  I would first like to say thank-you for an incredibly
effective program (it took me a while to get used to it, but now I am
quite impressed).  

The only remaining problem comes from the fact that I have an ADSL
connection at my home and the pppoe changes my IP address every once in
a while.  I have set my sip.conf 'host=' command up with a dyndns
hostname and everything works when I start *.  The moment the IP address
changes, though, incoming calls continue to work but outgoing calls give
me a "maximum retries exceeded" error, and my Dial command exits after
about 3 seconds with "NOANSWER".  I have confirmed that this is caused
by the change in IP address by restarting *, successfully making a call,
rebooting my DSL router to have it get a new IP address, waiting for
dyndns to register the change (and confirming that this is correct), and
then immediately making another call that has this problem.  When the IP
address doesn't change, I have confirmed that outgoing calls work after
several days.  A 'service asterisk restart' always gets the outgoing
calls working again, but it seems odd that I would have to restart * so
regularly. 

I am assuming that either * or the remote computer is either doing the
DNS lookup once and caching the IP address or there is a socket that is
opened and kept open through the IP address change and not reconnected
afterward (shouldn't the socket on both ends figure out that the
connection is no longer good and reconnect?).

As an ugly hack, I am tempted to have a cron job check for changes in
the ip address and restart *.  The problem with this (or one of them) is
that I have to somehow make sure that it isn't in the middle of a phone
call when it does this.  Is there a more elegant way of doing this?

Am I doing something wrong?

(And although getting a static IP would be the most elegant solution,
that really isn't an option now.)

Thank-you in advance,
Larry


<-------------- sip.conf

[general]
externip=<MY_HOSTNAME>.dyndns.org
bindaddr = 0.0.0.0
port=5060
localnet=192.168.0.0/255.255.255.0
disallow=all
allow=gsm
allow=slinear
allow=ulaw
allow=alaw
context=incoming
dtmfmode=inband
register => <MY_NAME>:<MY_PASSWD>@sip.broadvoice.com
tos=0x18
srvlookup=yes
nat=no

[Broadvoice]
type=peer
username=<MY_NAME>
fromuser=<MY_NAME>
secret=<MY_PASSWD>
host=147.135.8.129
context=sip
fromdomain=sip.broadvoice.com
canreinvite=no
dtmfmode=inband
nat=no

[broadvoice-incoming]
type=peer
dtmfmode=inband
host=147.135.8.128
context=incoming
qualify=yes
canreinvite=no
disallow=all
allow=gsm
allow=slinear
allow=ulaw
allow=alaw
insecure=yes
nat=no

[broadvoice-incoming2]
type=peer
dtmfmode=inband
host=147.135.0.128
context=incoming
qualify=yes
canreinvite=no
disallow=all
allow=gsm
allow=slinear
allow=ulaw
allow=alaw
insecure=yes
nat=no


<----------------------- the extension I am calling on
[trunkld]
;
; US long distance context accessed through trunk
;

;Pattern match US long distance calls
exten => _NXXXXXXXXX,1,Dial(SIP/1${EXTEN}@broadvoice,20)
exten => _NXXXXXXXXX,2,Goto(error-${DIALSTATUS},1)
exten => _NXXXXXXXXX,3,Congestion
exten => _NXXXXXXXXX,102,Busy