For SSH it is possible to disable the DNS reverse lookup(-u0):
https://www.linux-tips.org/article/92/disabling-reverse-dns-lookups-in-ssh
But this can impact other sshd options:
SSH slow to login?...
I was bored... :)
IFS=;who -ub | while read LINE;do IP=$(echo $LINE|sed -n "s/.*(\(.*\)).*/\1/p"|xargs -I{} dig +short {});echo $LINE|sed "s/(.*)/($IP)/g";doneMaybe there is a more elegant way.
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