This is a frequently asked question, especially from folks who troubleshoot fax in VoIP networks. Until today, I would have said “I have never seen it. That does not mean it can’t be done.” I also would have admitted that it is above my pay grade.
But that all changed today.
I found this: https://github.com/minektur/t38faxcap
This is a free and open source command line utility to extract T.38 fax images from PCAP files and export them as TIFF files. You put in a pcap file that has a sip-phone call with a fax that has T38-sent pages in it. You get out a set of tiff files representing each page that was sent via T38.
There are dependencies, and there is a sample to test your installation and configuration.
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