Glad it worked and thanks for letting us know.
Not surprised you hesitated resetting the modem. Its a real pain setting up again and I wouldn't do it unless I really had to.
Hope the fix holds.
First thing that popped into my head this morning was your last post. For future readers and yourself, the issue almost certainly would have been some thing in the parental control feature.
Thanks for your thoughts, very much appreciated.
I only have "time restriction" set to my children mobiles and PCs (mac addresses) in the parental control since installation 6 months ago so that they would not be deprived from rest/sleep hours. 🙂
Not 100% sure now, I will keep it in mind if this happen again, then I will have to find alternate solution to implement parental control.
The reason it did not occurred to me because nothing has changed since then and this weird issue just started on the 17 Nov morning when we first notice the problem. Another point that I missed to mention (if valid) was that I have a VPN connection to my work and it works fine when I was accessing via my VPN connection, hence my primary suspect was something must have changed in the Optus network in my area be it security or DNS, but you have a very good valid point that many would have been affected in my area.
Moreover it's just a handful of sites (mostly secured sites) that failed and not all. Coincidentally NBN is rolling in to my area this period and I have heard too many wierd scary issues arises at implemenation of NBN thus my first thought relating to it.
Yep. A lot of factors to consider there.
Not suggesting you changed the parental control setup, but just that something might have gone crazy internally. It would just be where I'd look first if the issue arrises again.
Good Luck migrating to the NBN