My friend had a visitor and she was able to link her smartphone to the wireless network.
Now he is worried she could read his email and his files.

Only the landlord has control of the modem.
Can he do anything besides a Firewall?
 

Landlord = "Free Wireless".

 

1 - Use a -good- Firewall.

2 - She (anyone else) can access NOTHING from another Device unless the files/folders are Shared.

3 - She (anyone else) would need a UserID to access it.

 

Generally, an "open" Wireless setup just allows -anyone within range- to connect to the lan/wan -but- the PC's have to have File and Printer Sharing activated and that means anyone accessing the PC -must- have a UserID defined. That's why you should -disable- the Guest Account (usually the Default setting) and set a Password for the Administrator account (renaming it is a good idea too).

 

The fears are -somewhat- unfounded. She would have to be one savvy hacker!

 

HTH

Thank-you. We won't worry about it then. I will have him check the file sharing just to be sure, but probably it is already set properly.

Are some firewalls better than others? Is this something he should take a look at?

We don't know how savvy she is but she might want to cause problem and could learn how to if she wanted.

And thanks again for answering the question, and explaining so we won't worry now.