ssh-resethost

#!/bin/sh

reset_host() {
    all="$1 $(dig +short $1) $(dig +short aaaa $1)"
    for ident in $all
    do
        ssh-keygen -f ~/.ssh/known_hosts -R $ident
        ssh-keyscan $ident >>~/.ssh/known_hosts
    done

}

if [ $# -ne 1 ]; then
    while read line; do
        reset_host $line
    done;
else
    for h; do
        reset_host $h
    done
fi