@mshahzad - at one stage the F@ST5366 TN was fixed to only use Optus DNS Servers which irritated some users who wished to use their own preferred DNS servers, so not sure if that will impact your preferred NBN RSP service and uncertain of the current state of play. Wasn't clear if you are migrating from ADSL or are currently on NBN with another provider. In the NBN configuration, you don't need to have any Line Filter connected to the telephone cable at the wall socket end.
The original product release post has grown to 17 pages! - you might find some up to date information there. https://yescrowd.optus.com.au/t5/Broadband-Telephony/New-Optus-supplied-modem-Sagemcom-5366TN/td-p/5...