This is a common question. You might default to asking who is fronting to try to be a good ally – thinking that knowing whom you’re talking to helps validate that alter as an individual. And for some alters in some situations, it might. However, the consensus answer to this question is that no, you should not ask who is fronting until you have established with a system that it’s something that makes them feel validated and they want from you.
If a system is not specifically talking about DID/OSDD they are often naturally masking, even if the ally doesn’t know it. Even if they’re out to you as being a system, masking is a natural defense mechanism that systems have built up throughout their lives. For many alters, it’s a more comfortable, easy, and safe feeling than unmasking. When someone asks who is fronting, it can feel very unsafe. Having your disorder called out like that can feel incredibly jarring and frightening. Remember that DID exists to be hidden! Having it brought into the light outside of the system’s own control can create panic. Additionally, if the alter who was fronting wanted to continue masking, you’ve now put them in the uncomfortable position of feeling like they need to lie to you that they’re not themselves.
For these reasons as well as others, don’t ask this question until you’ve established whether the system is okay with it. Even if one alter loudly proclaims their presence every time they’re out, that doesn’t mean the system as a whole has agreed to give you that kind of information whenever you ask.
(If you’re having a conversation where who is fronting is highly relevant, or the conversation is surrounding their disorder already, it may be a more appropriate time to ask who is fronting, but only if you’ve established it’s okay first. Respect the system’s boundaries.)