There are some architectural things to consider when using SIP2, since it was never meant to be a web backend. First, you should consider limiting, queing and batching your messaging to the SIP2 responder. It may not be able to handle a flood of messages. Second, you'll need to implement some security. SIP2 does allow for encryption between host and client but its up to the ILS vendor to provide this capability and then for individual libraries to implement it. You may consider sending all your requests from your web server to the SIP2 server through an SSH or VPN tunnel.