Question

I have a VPS server and a client is asking for SSH access on their hosting account.

I can allow this through the user setup for that particular account but will they be able to admin the entire server then?

I am worried their developer might start installing modules and break my other clients’ sites.

Answer 1

Does your VPS come with any control panel ? If so, its usually safe to allow SSH access. However, here is what I would do.

1. Find out why the client wants SSH access. This is not a conclusive method but would give you a chance to provide alternative solutions if you are uncomfortable enabling SSH access. Note that a lot of hosting service providers, small and large, do not allow SSH access (atleast not without making it so hard that the casual client refrains from asking).
2. For your mental comfort, create a SSH account for yourself and login with SSH access. Try to see what you can do beyond that specific account. If your test SSH access does not allow you any access beyond that test account, you know that the other guy cant do much either.