While "SSIS275" may look like a technical product name at first glance, it is not a standalone software tool or a "free" version of Microsoft SQL Server Integration Services (SSIS). Instead, in the world of database management and performance tuning, specifically refers to a wait type code — ASYNC_NETWORK_IO —which often appears when using SSIS.
If "ssis275 free" refers to an SSIS package/component versioned or named ssis275 and you want a free/open-source usage guide: ssis275 free