RSFirewall tries to identify the original IP address by looking at different HTTP headers. A bypass is possible due to the way it is implemented.
[
{
"vendor": "Unknown",
"product": "RSFirewall!",
"versions": [
{
"status": "affected",
"versionType": "custom",
"version": "0",
"lessThan": "1.1.25"
}
],
"defaultStatus": "unaffected",
"collectionURL": "https://wordpress.org/plugins"
}
]