That should be the replace function which performs word replacements in documents.
Answer:
The title of RFC 4890 is "Recommendations for Filtering ICMPv6 Messages in Firewalls" and it was published in 2007.
Explanation:
RFC 4890 is the memo that was published in 2007. This document is about the recommendations of filtering messages that are harmful and having security risk for Internet Control Message Protocol ICMP version 6.
In this document different types of risk associated ICMPv6 protocol while forwarding messages. This memo recommends filtering techniques to drop the harmful messages and make the communication secure.
