[amyjess]

I honestly don't see how this can pass OSI or DFSG approval. It's a blatant violation of rule 9, which prohibits restrictions on distribution of other software.

[zzzcpan]

Only if you think that related software necessary to make and run the service is "other software" and not an improvement over the primitive default service.

[metheus]

There is no restriction, only the requirement that the systems that make your service run be made available under the SSPL.

[amyjess]

If your license places any requirements on software that is not a derivative work of software you own the copyright to, the license is nonfree by the standards of the OFSI and the DFSG and probably others.