Using appengine/socket calls to access FTP files

[Jens-Uwe Mager]

I have to ingest data files from various sources in my appengine app, and one of them has reliability problems with their HTTP service. So they are referring me to their FTP server, which supposedly is running much more stable. I did now try to access their FTP Server using appengine/socket, and everything works nicely using my local dev_appserver.py. Upon deploying to appengine I cannot get this to work, I always get timeout errors. Is it possible that FTP is filtered at the network level at Google that I cannot do outbound sockets this way? By the way, due to several compatibility problems I am still using the old go runtime.