Let's assume I just installed Ubuntu on a laptop. This laptop may be used in different networks with different security measurements (at home, university, work place).
Is there anything that should be set up to prevent unauthorised system access/data leak or other security breaches, besides using a supported OS version, not installing shady software/repositories and such?
Are there any "hidden" settings regarding remote access or firewall configurations that should be defined to make the system less vulnerable?
samba
,apache
,ssh
( I do not mentiontelnet
)