I have a receive-only VOIP account with a small-time company in Poland. Not much in the way of support or features, and sporadically offline, but okay. I bought a local DID number from it.

What FOSS Windows or Linux software might I be able to use on a virtual server that

  1. has the ability to auto-answer calls after a timeout of N seconds (or X rings) because I am not picking up the line elsewhere, playback a greeting and record a voice mail,

  2. Optionally, forward the recorded voice mail to an email address.

    Something much, much simpler than having to setup an Asterisk server. (However if you see a very focused HowTo that applies, or with FreeSwitch or similar, please share.)

Better yet, is there a free cloud-based solution somewhere, sparing me the need to deploy this software on my own, having a PC always on?

Maybe some indirect way using eg. IFTTT, such that supplying my SIP credentials in some (web?) client will trigger an email + audio file attachment?

  • Did you find something? Sep 21, 2016 at 15:28

2 Answers 2



  • create announcement file (wave S16LE, 8ksps); it must be as long as the longest call voicemail should record as call would be disconnected when file would end, thus it should consist of few seconds of prompt, period of silence and perhaps warning at the end that call is about to be terminated
  • configure softphone to register to your provider, enable recording (mono recording mode would be fine), test it
  • set softphone audio input device to "Wave file", select your announcement
  • enable auto answer with delay of your choice
  • for maintenance-free operation make sure RTP timeout is set to e.g. 60 in "Network" tab

It is Win32 application, but it should also work with Wine (there are few problems but usually not critical).

If you need multiple channels (calls) recorded same time you would need multiple application instances.

Personally I would prefer direct access to recordings via network mapped drive / shared directory, but using mail should be possible if combined Lua scripting with some command line mail client: http://tomeko.net/software/SIPclient/howto/script_examples.php. Example script reads name of record file when call is disconnected and passes it as argument to mail client or any other application with ShellExecute function call. There seem to be (only) few command line clients for windows available, but I can't recommend any.

Attachment size for e-mails might cause problems as softphone recordings are uncompressed thus 1 minute recording takes ~1MB. Perhaps some batch file can be used to compress wav file to e.g. Opus in OGG container and send it as mail.


If you are not a FOSS-fanatic, i.e. if this is not a critical requirement, Google Voice will be just fine for you.

Just sign up for an account and it has all you need: you can pick up a US DID for free, it has built-in voicemail, and it can send recorded voicemails to email. Voicemail greetings are customizable.

  • Not Applicable to the rest of the world outside USA. :(
    – Marcos
    Oct 13, 2020 at 20:56
  • There are ways to sign up even for non-USA, just google a lil` bit ;) And you can perfectly forward your Polish DID calls to GVoice to record them
    – Suncatcher
    Oct 15, 2020 at 9:49

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