Yesterday eve I had to add a laptop to my network which is using MAC address filtering. The laptop ran Windows Vista and I tried to locate its MAC address by using the good old ipconfig within a command prompt. This gave no results as apparently the network details only get listed once an actual network connection is made. As you probably have realised this is a catch-22 situation as without the MAC address registered on the router I was never going to make a network connection in the first place…!
Actually the weird thing is that the MAC address is normally on a sticker on the bottom of laptops, but in this case there was no such sticker.
Google as in most other cases provided a quick fix by pointing me in the right direction. There is a command specifically for this task named funnily enough: getmac.
Today using the version of Pidgin that came with Fedora10 I received the following certificate prompt:
Accept certificate for ows.messenger.msn.com?
The root certificate this one claims to be issued by is unknown to Pidgin.
The majority of cases of unknown certificate issuers are due to the chain of trust breaking down. This break down in the certificate chain is mainly caused by the software in question not including the intermediate certificate authorities certificates. Without these intermediate certificates the software can not verify through the certificate hierarchy up till the root certificate and therefore prompts the user about what to do.
The options I received in the Pidgin prompt were:
View certificate
Accept
Reject
Upon selecting “View certificate” I am presented with the following details:
Common name: ows.messenger.msn.com
Fingerprint (SHA1): a9:9c:2d:ee:4a:d1:c8:7d:a7:c5:c3:05:32:98:5f:ee:57:87:73:8a
Activation date: Tue Jan 29 14:37:21 2008
Expiration date: Wed Jan 28 14:37:21 2009
So far everything looks as it is a bona fide certificate but to verify the identity completely I load the page https://ows.messenger.msn.com/ in Firefox. As expected no certificate warnings were received and I opened the certificate viewer to see its details and confirmed the data matches up with the data received in Pidgin:
Certificate Viewer
I can safely trust this certificate as Firefox has verified through the certificate chain that all intermediate certificates are valid too:
Certificate Chain
This certificate is simply used by Microsoft for the Live Messengeroffline messaging service. Although you normally would trust verified certificates it did happen in the past that certificates were incorrectlyissued to the wrong people. So always be cautious!
