Client on Firewall

Hi Everyone!

I just want to know on how my client would configure thier network as they have Firewall as they see that this will be an issue when we do our integration setup. I've suggested to them already to use the SAP US IP Range to be included in thier white list of IP addresses for a direct connection but the client dont want to use such direction connection, they are suggesting that they should create a VPN to allow connection from thier SAP System to Cloud For Travel and Expense, on this I would like to know if such VPN is supported in Cloud for Travel and Expense?

Regards,

Joey