Working for new company - requesting references

When a company asks for a reference, legally what questions do / can they ask your previous employer and legally what replies can / cannot be given.

Is it usualy just to confirm start / end dates and to confirm that the person was an employee, their role and leaving salary?

Are questions allowed to be asked on things like sickness record, timekeeping, performance etc?

The new company can ask what they want but most companies will only give confirmation that your worked there. I've never heard of anyone divulging a persons salary and I would say that it may well be illegal to answer.