By default asterisk only sends ‘180 Ringing’ when RING event is requested.
To send a ringback tone using early media two settings must be changed.
prematuremedia=no ;this does the exact opposite of what everybody thinks it does...
progressinband=yes
Test with Dial option ‘r’ and see if you get 183 Session Progress.
When you want to convert typical MP3/WAV files for your PBX like Asterisk, you can use sox and lame to do it easily.
lame --decode somemp3file.mp3 output.wav
First, convert the MP3 to WAV file.
Then,
For u-law:
sox -V output.wav -r 8000 -c 1 -t ul result.ulaw
For GSM:
sox output.wav -r 8000 -c 1 result.gsm resample -ql
Pre-converting your input sound files usually give much better results than using internal modules for transcoding.
If you have your asterisk server connected to the public internet, there always will be some bad boys trying to brute-force into your PBX.
A few months before I found my asterisk server dead. Looking through the logs I was surprised to find that it was the spammers trying to brute force the password, eventually filling up the entire disk with error logs and crashing the server. Unfortunately that server operated on a single partition scheme with everything allocated for / .
[Sep 12 20:24:02] NOTICE[28190] chan_sip.c: Registration from '"249"
[Sep 12 20:24:02] NOTICE[28190] chan_sip.c: Registration from '"249"
[Sep 12 20:24:21] NOTICE[28190] chan_sip.c: Registration from '"497"
[Sep 12 20:24:21] NOTICE[28190] chan_sip.c: Registration from '"497"
Yesterday same thing happened again, but luckily I found it early enough to block it before it crashes the server.
iptables -I INPUT -s 37.8.53.84 -j DROP
I used iptables to filter out those garbage packets.
To view the blocked ip list use the following command.
iptables -n -L
It can be rather annoying when it comes to a production server where there are so many logs to inspect.
I recommend creating a script to automate the tasks if that is the case.