The embodiment of the invention discloses a communication security
processing method, a relevant apparatus and a
system, wherein the method comprises the steps of a security gate receiving a report transferred by a host, and the report is transmitted from a source device to a target device; determining a
security domain that a first user belongs to when
logging in the source device, and a
security domain that a second user belongs to when
logging in the target device. If the
security domain that a first user belongs to is the same to the security domain that a second user belongs to, conduct security
processing to the report according to domain-inside
security policy; and if the security domain that a first user belongs to is different from the security domain that a second user belongs to, conduct security
processing to the report according to inter-domain
security policy. According to the embodiment of the invention, the security domain that a user belongs to can be determined according to the
user information, and different security processing policies can be conducted based on whether the security domains are the same or not, therefore, safe isolation is realized, and communication security among users are guaranteed.