Sonic.net SMTP IP ranges

[wscoville]

I'm using mail.sonic.net to send out from my business account which has a different domain and is hosted at an Exchange provider. I'm using IMAP through the provider. This has worked fine but out company switched to a different email filtering provider and now any emails to other internal users are being blocked. The email filtering service is wiling to put in a policy allowing inbound from my account using mail.sonic.net but needs the IP address range - they will not use just DNS. What is the SMTP Ip address range used by Sonic?

Thanks

[kgc]

There's no guarantee that this will not change at any time but our current customer outbounds are 64.142.111.80 and 64.142.111.50.

Perhaps they can do this by dns, allowing *.mail.sonic.net or using SPF by including mail.sonic.net?