A quick note for those using SiteMinder and Liferay...
Liferay likes the Tilde (~) character, and uses it quite often for friendly URLs and other reasons.
When fronting with SiteMinder, though, you may run into return code 500 for URLs with the tilde character in them.
This is actually a default SiteMinder configuration thing, SiteMinder treats tilde (and others) as "bad characters" and will return a 500 when they are found.
The default SiteMinder configuration has this setting:
You want to override the default configuration to allow the tilde character:
After making this change, restart the daemons and you should be back in business.