In the output of `last`, what does suffix ".d" after an IP address mean?
59.224.XX.178.d
is not an IP-address but a hostname, or rather part of it.
Last tries to do a reverse lookup and stores both the resulting hostname and ip-address for the remote host. By default the hostname gets displayed and long ones get truncated to display nice columns.
Try last -a
to display the hostname on the last column without truncation. or last -i
to display the ip-address.
Compare:
$ last -n 1 name
name pts/0 host38.resource. Mon Aug 17 15:46 - 16:00 (00:13)
$ last -n 1 -a name
name pts/0 Mon Aug 17 15:46 - 16:00 (00:13) host38.resource.hq.example.com
$ last -n 1 -i name
name pts/0 10.9.8.38 Mon Aug 17 15:46 - 16:00 (00:13)
The -i makes 'last' show the remote hostname in dots and numbers IP address format instead of trying to display the hostname.
I am not sure what the '.d' suffix is, nor can I find out anything on google. I can only guess it is trying to do a reverse lookup and is giving you part of a hostname and truncating it, although i thought you must specify -d to do hostnames.