the username and password on my CM500V router do not work.
I can connect to the modem using
but can't access parental controls with the modem username an password. All the other usual ones don't owkr either (eg. admin, password)
Hi - usually the modem will either have printed branding on the rear or a sticker indicating the Default User ID and Password. On three newer Optus modems I have seen, 'optus' was assigned as the User ID. If someone has changed the log-in details, the default information can be restored by Factory Resetting the modem by inserting a paperclip into the Restart hole for 10 seconds with power ON.
My apology - I should have read your post more carefully and hoping this may assist.
The Netgear CM500v is a HFC Cable modem with a LAN port and Voice sockets for phone service. It is possible to connect one computer to its LAN port but usually but not recommended as it would usually not have a Firewall to protect the PC. It is usually connected to another Optus Modem like the F@ST3864AC or F@ST3864V3AC or later to provide Wi-Fi and LAN connectivity for multiple devices so that they can all access to the Internet at the same time.
Do you have an additional Optus modem as described above - if so, the IP address for it is as you have typed it in your post. From memory, you should be presented with an Optus Welcome or Home screen depicting four icons or a graphic depicting your network that allow you to see basic information about your network. If you select the Setup and Configuration or Advanced Settings link, you will then be challenged for a User ID and Password which is 'optus' for the User ID followed by the password which is the one printed on the label (it is the same as the modem's default Wi-Fi password). After you credentials are authorised with these inputs, the Parental Control menu is then viewable along with Advanced Settings of the F@ST3864... Modem.
If the default credentials don't work, try Factory Resetting as described in my earlier post. Sometimes settings are altered within the modem due to power outages or by others without the knowledge of the owners, particularly in matters related to Parental Controls.
Generally, front end HFC Modems on NBN are not accessible by customers. Not sure if you are on NBN or are not connected to the NBN as yet. Hope this helps.