erc-disable-ctcp-replies

erc-disable-ctcp-replies is a variable defined in `erc.el'.
Its value is

nil

Documentation:
Disable replies to CTCP requests that require a reply.
If non-nil, then all incoming CTCP requests that normally require
an automatic reply (like VERSION or PING) will be ignored. Good to
set if some hacker is trying to flood you away.

You can customize this variable.