soluzioni

Per capire il senso esatto della domanda, osserviamo che le macchine della aula 4 condividono le home e la posta. 
steffe@lab1:~$ date
Sun Nov  1 12:37:38 CET 2015
steffe@lab1:~$ df
df: `/var/lib/lightdm/.gvfs': Permission denied
Filesystem                                1K-blocks      Used  Available Use% Mounted on
/dev/sda3                                  72091984   1121936   67307968   2% /
udev                                        1665996         4    1665992   1% /dev
tmpfs                                        335756       956     334800   1% /run
none                                           5120         0       5120   0% /run/lock
none                                        1678768      1488    1677280   1% /run/shm
/dev/sda4                                 148992340  14987600  126436356  11% /usr
/dev/sda2                                  48060008   2869164   42749492   7% /boot
/dev/sda5                                 163409364   3188808  151919808   3% /var
student.local:/data-home/home            2166923656 744492800 1312334472  37% /student/home
student.local:/data-mail/mail             915936560 191062216  678324384  22% /student/mail
student.local:/data-homenb/home.NoBackup 2166923656  33493416 2023333856   2% /student/homenb

Dunque è student il server NFS che esporta home, homenb e mail. Chiediamoci quali altre macchine possono montare tali filesystem da student: 
steffe@lab1:~$ showmount -e student
Export list for student:
/data-mail-bak             192.168.40.7
/data-homenb/home.NoBackup 192.168.73.199,192.168.73.198,192.168.73.197,192.168.73.196,192.168.73.195,192.168.73.194,192.168.73.193,
192.168.73.192,192.168.73.191,192.168.80.92,192.168.80.91,192.168.70.146,192.168.70.145,192.168.70.144,192.168.70.143,192.168.70.142,
192.168.70.141,192.168.70.140,192.168.70.139,192.168.70.138,192.168.70.137,192.168.70.136,192.168.70.135,192.168.70.134,
192.168.60.133,192.168.60.132,192.168.60.131,192.168.60.130,192.168.60.129,192.168.60.128,192.168.60.127,192.168.60.126,
192.168.60.125,192.168.60.124,192.168.60.123,192.168.60.122,192.168.60.121,192.168.50.182,192.168.50.181,192.168.50.180,
192.168.50.179,192.168.50.178,192.168.50.177,192.168.50.176,192.168.50.175,192.168.50.174,192.168.50.173,192.168.50.172,192.168.50.171
/data-home/home            192.168.40.7,192.168.73.199,192.168.73.198,192.168.73.197,192.168.73.196,192.168.73.195,192.168.73.194,
192.168.73.193,192.168.73.192,192.168.73.191,192.168.80.92,192.168.80.91,192.168.70.146,192.168.70.145,192.168.70.144,192.168.70.143,
192.168.70.142,192.168.70.141,192.168.70.140,192.168.70.139,192.168.70.138,192.168.70.137,192.168.70.136,192.168.70.135,192.168.70.134,
192.168.60.133,192.168.60.132,192.168.60.131,192.168.60.130,192.168.60.129,192.168.60.128,192.168.60.127,192.168.60.126,192.168.60.125,
192.168.60.124,192.168.60.123,192.168.60.122,192.168.60.121,192.168.50.182,192.168.50.181,192.168.50.180,192.168.50.179,192.168.50.178,
192.168.50.177,192.168.50.176,192.168.50.175,192.168.50.174,192.168.50.173,192.168.50.172,192.168.50.171
/data-mail/mail            192.168.73.199,192.168.73.198,192.168.73.197,192.168.73.196,192.168.73.195,192.168.73.194,192.168.73.193,
192.168.73.192,192.168.73.191,192.168.80.92,192.168.80.91,192.168.70.146,192.168.70.145,192.168.70.144,192.168.70.143,192.168.70.142,
192.168.70.141,192.168.70.140,192.168.70.139,192.168.70.138,192.168.70.137,192.168.70.136,192.168.70.135,192.168.70.134,192.168.60.133,
192.168.60.132,192.168.60.131,192.168.60.130,192.168.60.129,192.168.60.128,192.168.60.127,192.168.60.126,192.168.60.125,192.168.60.124,
192.168.60.123,192.168.60.122,192.168.60.121,192.168.50.182,192.168.50.181,192.168.50.180,192.168.50.179,192.168.50.178,192.168.50.177,
192.168.50.176,192.168.50.175,192.168.50.174,192.168.50.173,192.168.50.172,192.168.50.171
Si noti che questi sono gli indirizzi non routabili (visibili solo sulla LAN) delle macchine delle aule 3 e 4 e di ssh1 e ssh2.

E quali stanno montando realmente dei file systems da mail ? 
steffe@lab1:~$ showmount -a student
All mount points on student:
192.168.50.171:/data-home/home
192.168.50.171:/data-homenb/home.NoBackup
192.168.50.171:/data-mail/mail
192.168.50.172:/data-home/home
192.168.50.172:/data-homenb/home.NoBackup
192.168.50.172:/data-mail/mail
192.168.50.173:/data-home/home
192.168.50.173:/data-homenb/home.NoBackup
192.168.50.173:/data-mail/mail
192.168.50.174:/data-home/home
192.168.50.174:/data-homenb/home.NoBackup
192.168.50.174:/data-mail/mail
192.168.50.175:/data-home/home
192.168.50.175:/data-homenb/home.NoBackup
192.168.50.175:/data-mail/mail
192.168.50.176:/data-home/home
192.168.50.176:/data-homenb/home.NoBackup
192.168.50.176:/data-mail/mail
192.168.50.177:/data-home/home
192.168.50.177:/data-homenb/home.NoBackup
192.168.50.177:/data-mail/mail
192.168.50.178:/data-home/home
192.168.50.178:/data-homenb/home.NoBackup
192.168.50.178:/data-mail/mail
192.168.50.179:/data-home/home
192.168.50.179:/data-homenb/home.NoBackup
192.168.50.179:/data-mail/mail
192.168.50.180:/data-home/home
192.168.50.180:/data-homenb/home.NoBackup
192.168.50.180:/data-mail/mail
192.168.50.181:/data-home/home
192.168.50.181:/data-homenb/home.NoBackup
192.168.50.181:/data-mail/mail
192.168.50.182:/data-home/home
192.168.50.182:/data-homenb/home.NoBackup
192.168.50.182:/data-mail/mail
192.168.60.121:/data-home/home
192.168.60.121:/data-mail/mail
192.168.60.122:/data-home/home
192.168.60.122:/data-homenb/home.NoBackup
192.168.60.122:/data-mail/mail
192.168.60.123:/data-home/home
192.168.60.123:/data-homenb/home.NoBackup
192.168.60.123:/data-mail/mail
192.168.60.124:/data-home/home
192.168.60.125:/data-home/home
192.168.60.126:/data-home/home
192.168.60.127:/data-home/home
192.168.60.128:/data-home/home
192.168.60.129:/data-home/home
192.168.60.129:/data-homenb/home.NoBackup
192.168.60.130:/data-home/home
192.168.60.130:/data-mail/mail
192.168.60.131:/data-home/home
192.168.60.132:/data-home/home
192.168.60.133:/data-home/home
192.168.60.133:/data-mail/mail
192.168.70.134:/data-home/home
192.168.70.134:/data-homenb/home.NoBackup
192.168.70.135:/data-home/home
192.168.70.136:/data-home/home
192.168.70.137:/data-home/home
192.168.70.138:/data-home/home
192.168.70.138:/data-homenb/home.NoBackup
192.168.70.138:/data-mail/mail
192.168.70.139:/data-home/home
192.168.70.140:/data-home/home
192.168.70.141:/data-home/home
192.168.70.141:/data-homenb/home.NoBackup
192.168.70.142:/data-home/home
192.168.70.143:/data-home/home
192.168.70.144:/data-home/home
192.168.70.145:/data-home/home
192.168.70.146:/data-home/home
192.168.73.191:/data-home/home
192.168.73.191:/data-homenb/home.NoBackup
192.168.73.191:/data-mail/mail
192.168.73.192:/data-home/home
192.168.73.193:/data-home/home
192.168.73.194:/data-home/home
192.168.73.194:/data-homenb/home.NoBackup
192.168.73.194:/data-mail/mail
192.168.73.196:/data-home/home
192.168.73.196:/data-homenb/home.NoBackup
192.168.73.196:/data-mail/mail
192.168.73.198:/data-home/home
192.168.73.198:/data-homenb/home.NoBackup
192.168.73.198:/data-mail/mail
192.168.80.92:/data-home/home
steffe@lab1:~$
 
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Laboratorio di Comunicazione mediante Calcolatore - Sergio Steffè - AA 2016/2017 - PISA