Hello and welcome to my User Tip
I will explain in short some issues in regards to safeguarding your Internet WiFi at your home or office.
Refer to your router's user manual for detailed changes to your router's settings or call a local Mac/PC specialist if this is beyond your experience.
I offer no instructions, only these tips to make sure you're as secure as possible online.
There is only ONE secure WiFi router standard and that's WPA2(AES), both WPA and WEP are cracked.
Newer Mac's are not connecting to WEP Encrypted so I hear, since WEP is cracked having it encrpyed makes little sense, but some older routers may still have it.
If you have a Airport Express or Extreme, Apple provides software updates (using Airport Utility) for the router to updates it's firmware.
If your using a third party router or router/modem combination, it's important to check for firmware updates and apply them.
For most users, a router has to have remote access turned off, a admin password and a 'guest for Internet use only' password.
If possible, turning off PING can assist in not responding to knocks on the door to describe itself, thus reduce the traffic on the router.
The admin password for the router should be greater than 20 random characters/case/symbols to prevent brute force attacks via the Internet, it shouldn't be used or stored on any computer other than entering it to access the router for admin purposes, then by the most secure machine on the network, usually a Mac.
The reason I give is simple, if the computer with the routers Admin password gets compromised, then malware can have access to the router, change the DNS setting and have a adverse effect on other computers and devices on the local area network.
The 'guest for Internet use only' password can be less characters to fit the requirements of devices, but if possible also should be longer than 20 random characters. This is used for all computers and devices on the network.
If you're having trouble with your WiFi, you perhaps need to use a "sniffer" software to determine what other WiFi's are in the area and the channel they are on so you can set your routers channel far away from theirs.
Computers remember the passwords of the Wifi that's entered into them, malware can glean this and hack the router, why you only use the Guest Access for all machines. Rotate the Guest Access password routinely to keep those you want off the network or sharing your password.
A router's MAC Address filtering doesn't work, nor does making your network "hidden" offer any protection from hackers of your Wifi and actually causes more problems for you in most cases.
If your tired of connecting your Mac every time it wakes up or you walk out of range? It's because of the hidden network you have, the Mac is not going to go around constantly asking to connect to a hidden network, that would reveal it was connected to one and somebody might like to find out why and follow you home.
Here are some security tips for those using "open" or coffee shop type Wifi locations
Your on THEIR network, which means if you don't have a secure HTTPS connection to the website you're visiting, your traffic can be observed and likely is being recorded.
If the network is open, or others are on it and it's not encrypted, others in the same area can watch your traffic.
The sites you visit, even if you have a secure connection, can be recorded by the Domain Name Server lookups your computer does to get the current IP address of the site.
The MAC Address of your computer or device is recorded by the router of the WIFi location.
Most banking and other sales sites have enabled HTTPS, so when you enter data it gets encrypted enroute, so look for that secure connection before entering any data. But that might not be enough for your tastes
About computers you use, but don't own
If you are using a computer at a school, work etc, on a network, that you don't have Admin level control over, fully expect it can and is remote monitored, remote viewable, meaning what your doing and seeing is appearing on another computer on the network.
If it's not on the network and you don't have Admin control over it, like a locked down portable school computer that's taken home at night by the student, fully expect to have "nanny" software installed recording one's activity for later observation. The reasons why they do this are: it's their property and your just a guest using it with no rights to privacy or ownership etc.
How to be as secure as possible at other wIfi locations?
Firefox web browser has a add-on from the Electronic Frontier Foundation called HTTPS Everywhere
This add-on will ask for a HTTPS session from every website you visit. Not all can provide it as all elements on a page have to be encrypted and some sites it's not practical (like video, or with advertisements) but many websites do including Apple, Google, Wikipedia etc. This offers some measure of protection on open Wifi networks.
Look in your web browsers URL bar for https instead of http, then you know you have a encrypted connection.
Second, if you don't want others to know what your Domain Name Server lookups are (so they don't know what websites your visiting)
Then your going to need to install DNSCrypt and change your DNS on your computer to OpenDNS in System Preferences > Network.
I should warn you that changing your DNS settings (from your ISP's given DNS) can make large downloads of Akamai based content that Apple (and others) delivers slower as it depends upon the closest server for faster downloads.
But you should be able to create a New Location in System Preferences > Network and use OpenDNS servers that way when on the open WiFi spots which are usually not good large scale download locations anyway because of all the others sharing the same connection.
Contrary to myth, changing one's DNS server isn't always faster. Use this free tool to determine.
So in other words, just don't search for "alternate DNS" online and enter any old IP addresses into your router or computer to change the DNS, it might be a scam, then you just compromised your own router.
Alternate DNS on your router
DNS stands for Domain Name Server, when you do a search for "apple" in Google and get a link for Apple.com, you click that link and a request goes to the Domain Name Server to ask for the current IP address (number like so 126.96.36.199 ) so your computer can connect to that site.
You can choose to type in 188.8.131.52 in the URL and press enter, but Apple might change servers or establish one closer to your location which would be faster, the Domain Name Server handles all this moving around and changes automatically.
If you choose to use a alternate DNS than the one supplied by your ISP, you may want to establish this on your home/office/school/library router so all devices on your network are using it. The advantages of alternate DNS come in the form of blocking attack sties, content filtering, etc. that your ISP doesn't supply such services.
The DNS side content filtering isn't 100% perfect as new stuff is created all the time, but it can be used to reduce the likelihood of accidentally coming across unwanted content.
Usually alternate DNS services provide automatic bad site filtering as a default setting and content level filtering options as a log in option.
Computers are not 100% secure, even Macs (especially one's not using the latest 2 OS X versions in circulation) but they are a bit more secure than Windows machines depending upon usage. There is malware targeting Mac's, so you take some pre-cautions in that regard.
Like with gambling, do not deal with amounts online that your not willing to risk losing.
Your bank will NOT issue a refund if a loss occurs, it's out of their responsibility what occurs on your machine. Far as they know, you transferred all your money to another bank and then withdrew it all or worse, they can claim you had a accomplice! So you see their position why they don't issue refunds, they would be scammed by many often.
It's rather easy to set up a secure savings account with more substantial funds and use a more accessible online/checking/debit account with less funds and transfer some from one to the other occasionally (but not via online banking of course) with either no or very limited overdraft protection, only keeping what one is willing to lose in the less secure accounts that is exposed to the world.
Four digit passwords used for ATM machines are incredibly weak, scammers have gotten clever and even create fake ATM machines for you to "lose" your card in and enter your password, which they then go drain your savings account every day until you decide to do something about it.
Some have gleamed personal information from you in other ways and then get a fake ID made and impersonate you at another branch, withdrawing huge amounts. You can setup a secret password with banks to use on special large amount accounts that don't see frequent activity and require a manual walk-in to access those accounts.
A good bank will take a photocopy of your id when the account is opened and use that as a secret check to confirm your identity hasn't been impersonated.