A database administrator contacts a security administrator to request firewall changes for a
connection to a new internal application. The security administrator notices that the new
application uses a port typically monopolized by a virus. The security administrator denies the
request and suggests a new port or service be used to complete the application’s task. Which of
the following is the security administrator practicing in this example?

Timestamps and sequence numbers act as countermeasures against which of the following types
of attacks?