[X4U] Mail asks for password

[Randy B. Singer]

On Jan 25, 2010, at 4:33 PM, zapcat wrote:

> I noticed that I have IPv6 set to "Automatic."
>
> Within the last year, I was advised to set it so, and while I don't  
> recall exactly what the issue was, I have the sense that it was  
> related to security..

IPv6 *might* provide some increased security *if* you use a name  
server that is compatible.  At this time, the latter is highly  
unlikely, and the increased security that you are concerned about  
might already have been retrofitted into IPv4 for the name server  
that you use.  The primary reason that IPv6 was developed was to  
provide for more IP addresses:
http://en.wikipedia.org/wiki/Ipv6

> Whether or not it does, do you know of any downsides to turning  
> IPv6 off?

The reason that turning IPv6 off may improve performance is that some  
DNS servers do not properly respond to IPv6 requests.  As a result,  
your computer has to time out waiting for a response and then try a  
secondary DNS server.

In recent versions of OS X, IPv6 typically is on (set to "automatic")  
by default, but not used.  You have nothing to lose by turning IPv6  
to "off" and then seeing if performance improves.  When I first  
turned it off, I tested it out by going to a Web site that I visit  
often that is typically slower to load than any other Web site that I  
have visited, Sports Illustrated:
http://www.si.com
It came up instantaneously, as it it had been cached!  I had never  
seen it do that previously.

Changing your IPv6 setting isn't immutable.  If you don't realize a  
performance improvement, just change it back to "automatic."  I can't  
think of any downside to trying this out.

___________________________________________
Randy B. Singer
Co-author of The Macintosh Bible (4th, 5th, and 6th editions)

Macintosh OS X Routine Maintenance
http://www.macattorney.com/ts.html
___________________________________________