You have a hybrid deployment of Exchange Server 2013 and Office 365.
The mail flow between Office 365 and the on-premises Exchange Server environment is routed through an Exchange Server 2010 Edge Transport server.
Your company is assigned a new set of public IP addresses.
A network administrator updates the external firewall address and all of the associated DNS records.
Office 365 users report that they cannot receive email messages from on-premises users.
You discover that outgoing email messages to Office 365 are in the Office 365 SMTP queue on an Edge server.
You need to ensure that the on-premises users can send email messages successfully to the Office 365 users.
Which tool should you use?