Accepted Solution

Modem password entry


Yesterday I received from Optus this Sagemcom Fast 3864 OP ADSL modem.  I have got it working no doubt on my internet.


I need to put in a password to protect this modem.  The instruction came with it said the Username is ADMIN and the Password is PASSWORD.  So I logged into this modem with  Went into the Management and Security section ready to password protect it.  It asked for Old Password and the New Password of my choice.  So naturally I keyed in the Old Password as PASSWORD and my new Password accordingly.  But the change failed.


Please assist, anyone.


Thank you.

Re: Modem password entry


Hi TheOne,


Does it give you any other error message other than "change failed"





Re: Modem password entry


No, only "Password change failed"

Re: Modem password entry


Just to be sure, you're trying to change the modem password and not the Wi-Fi password correct? They're 2 different things which means if you're entering the modem password in the "old password" section when trying to change the Wi-Fi password, it will fail due to the mismatch

I do not represent Optus. The views, opinions and advice expressed in my posts are my own

Re: Modem password entry


I use an dedicated TPLink Router.  Therefore, the Sagencom wifi was disabled. If I want to change the wifi password I would enter from the Wireless menu.


To change the modem password I entered from the Management, Access Control menus.



Re: Modem password entry


Hi TheOne, I've just had a conversation with our Networks team in relation to your query. With the current firmware on the Sagemcom Fast 3864, it is not possible to change the admin credentials. Though Networks is always working with Sagemcom on updated firmware and that feature may appear in future firmware versions.


It's not clear from your posts if you have ADSL or NBN with us as that particular modem is being provided for both types of connections. If you have ADSL, then any standard modem/router can be connected, you would just need to enter your Optus username/password. But if you have NBN, then our Sagemcom modem will need to be connected.

Re: Modem password entry


I have the Sagencom Fast 3864 connected into ADSL2+.  TP Link Router works fine connected into this modem.


At the moment I could get into Sagencom's configuration setting (via wifi or ethernet cable) directly by typing without any password because it will never even asked for one.


Not able to input a passward to protect the modem setting is unacceptable. Anyone who plugs an ethernet cable and a computer into this modem will be able to look into the settings and make changes.  Security is compromised.


Are you suggesting if I update the Sagencom Firmware I would be able to input a new password? 


Currently when I tried inputing a new password it would always asked for the old password (Menu said it's "PASSWORD") first.  So I keyed in PASSWORD.  I wonder the old password "PASSWORD" was correct, as suggested by the instruction manual?  I could send you a screen shot if there's a way to do so.


Please advise.


Thank you, Nghi.

Re: Modem password entry


Essentially that is correct TheOne, any device with physical access to your router or has the Wi-Fi credentials will be able to go into the modem and view settings. We work with Sagemcom on new firmware all the time to add new features but would not recommend you loading non-Optus supplied firmware into the router. This is to ensure we can continue to provide Tech Support and maintain a working connection.

Re: Modem password entry



We too have the same issue with the Sagemcom Fast 3864 modem. The concern raised by 'TheOne' is genuine - and the issue is 'A Bug' in the customized 'Optus Firmware' for the Sagemcom Fast 3864 modem. This is a 'Major Security Issue' - no one should be allowed to tamper with your modem settings without adequate authentication for the purpose. Wi-Fi credentials giving such Open Access to your Internet Modem is 'A Vulnerability' a flaw that can be very costly as data packets could be intercepted and diverted to an unlegitimate masquerading page - also commonly referred to as man-in-the-middle attack (eg. - Please Read and Escalate as a 'Priority One Issue'.

Re: Modem password entry


Hi @major (and @TheOne) I feel there may be some confusion around this. All routers worldwide come with a simple admin password; why is this you may ask? Because for the average customer, that level of security is fine. For someone to 'hack' into those settings would mean you would have to either provide them with your Wi-Fi password first (so it would be someone you know), or they would have to break into your house with a computer, and connect to your ethernet sockets so they are connected to the modem (in which case it's your home security you would be concerned about, not your network security).

Sure, someone with advanced IT/coding knowledge may hypothetically be able to access a home network with the right software tools, but that would be the case with any router and they'd need to have a reason to want to do it. The likelihood of this happening is very low, unless you are a government official with secrets that people may want to steal. The vast majority of so called 'hacking' on any home service is generally caused by someone in the house clicking on a malicious link, or opening an email attachment with a virus or malware enclosed. That said, your concern is certainly noted and I’ll provide this to our product team to take into consideration

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