Which IPsec mode includes the peer id information in the first packet?

Main mode in IKEv1 uses a six-packet exchange where the peer's identity is encrypted and sent within the third and fourth packets, thus protecting it from eavesdropping.

Quick mode is part of IKE Phase 2, which establishes the IPsec Security Association for data encryption and does not involve the initial peer identification process.

Aggressive mode is an IKEv1 Phase 1 negotiation method where the initiator sends its identity payload (IDi) and other security parameters in the initial packet. This allows for a faster three-packet exchange but means the peer's identity is transmitted unencrypted in that first packet.

While IKEv2 is a newer version of the IKE protocol, it has its own exchange types, and the characteristic of sending the peer ID unencrypted in the *first* packet is a specific feature of IKEv1 Aggressive Mode.