In general, 25G SFP (Small Form-factor Pluggable) modules are not guaranteed to work in 10G SFP ports. The primary reason for this is that 25G modules typically operate at a higher data transfer rate compared to 10G modules, and their electrical and signaling specifications may not be compatible.

While the physical form factor of the SFP module is the same, the underlying technology and signaling can differ. Plugging a 25G SFP module into a 10G SFP port may result in the devices not recognizing each other, or it may lead to unreliable communication and potential damage.

However, some devices and transceivers may support what is known as "dual-rate" functionality. This means that a single module can operate at multiple data rates, such as 10G and 25G. If a device explicitly supports dual-rate SFP modules, then it may be possible to use a 25G SFP module in a 10G SFP port, but this compatibility must be explicitly specified by the manufacturer.

It's crucial to consult the documentation and specifications provided by the equipment manufacturer to determine whether such compatibility is supported. Using modules outside the specified compatibility can lead to network issues, unreliable performance, and potential damage to the devices.