Webmethods IS has the ability to create an ftp/s port, however there is not an sftp option. Is there an alternative to implementing the IS to act as an SFTP server?
If with just standaloneIntegration Server, there is no way to allow IS to become SFTP server out of the box.
But you may purchase additional product called ActiveTransfer which is the Managed File Transfer solution built on top of IS to have that capability. Please contact your account manager for more info.
Yes unless you have licensed the SAG-MFT product (Active Transfer Server - IS) that brings WmMFT package components hosted on MWS, then you should be able to enable the IS act as an sFTP server (in/out)
or you might want consider an alternative approach:
Have you Partner send you a WS-Message with the informations on the file to be transferred and then fetch from Partner´s SFTP-Server with the existing built-in services.