Applications that use CORBA as the communication layer often face some restrictions for multi-domain deployment. This is particularly true when they have to face firewall/NAT traversal. Furthermore, nowadays there is no well-accepted unique or standardized solution adopted by all ORBs, compelling applications using this type of middleware to use proprietary solutions that sometimes do not address the environment restrictions in which they are deployed (e.g. impossibility to open firewall ports). This work presents and compares three solutions for firewall/NAT traversal by CORBA-based distributed applications, each one suitable for a specific situation and exploring its advantages. Examples of such situations are the possibility of open firewall ports or the possibility of start a TCP connection to the outside network.