Check the format and version
DWG and DXF are CAD drawing formats. DXF can be text or binary, so the extension alone does not describe its contents. If opening fails, check the authoring program and save version.
Check missing content
Drawings may depend on external references or separate fonts. Sending only the main file can leave content missing or change text appearance. Ask the sender which supporting files are needed.
Check units before measuring
If dimensions differ, inspect the drawing units and scale. Compare important dimensions with the original CAD application.
View the drawing in SnapCAD
The SnapCAD page links to the stores. Check your platform's listing for additional formats and 3D features.
Sources
Autodesk DXF overview, DXF export