[Asterisk-Users] A tidbit about one-way audio & ethernet aliases

Jeremy Jones jjones at westcomllc.com
Thu Mar 25 06:33:54 MST 2004

Hey all,

Thought I'd share a curiosity I found when trying to use heartbeat
software for asterisk failover (this may already be common knowledge to
some/many, but I hadn't seen mention of it yet).  The default ha-linux
ip-takeover script uses ifconfig to create an ethernet alias to which a
secondary IP address is assigned (i.e. eth0 is your main interface at, and the heartbeat script creates eth0:0 at  I had
been testing my asterisk configuration w/out heartbeat 'til I thought it
stable enough for production, then I turned on the heartbeat & left the
office to set up my first subscriber.  Imagine my shame...  No audio
from pstn to subscriber (using sip ata behind nat).  Seems the rtp
stream doesn't appreciate being directed at a secondary address.  

So, swapping out the default ha-linux ip-takeover script for one that
uses "ip" from the iproute2 package solved my problem.  (Perhaps this is
what Doichin Dokov had going on late last week?)

Jeremy Jones

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