G3100 DNS Rebind Protection and dnsmasq issues

[ajwe]

I upgraded to a G3100 router on June 10 and since that day the software I use to sync my phone and Windows computer – AkrutoSync – hasn’t worked. I get the following errors in the router’s system log:

2020 Jun 22 08:14:33     dnsmasq             warning              [SYS.4][SYS] possible DNS-rebind attack detected: servername

(where servername is the name of the server at AkrutoSync that handles the request)

I’ve reached out to AkrutoSync for help on this and they’ve asked me to find the “DNS Rebind Protection” settings on the router, but I’m unable to locate any such settings. I searched the router’s manual for that and also for ‘dnsmasq’ but came up empty.

Here’s how I think the AkrutoSync software works: On my phone, when it syncs, it reaches out to the AkrutoSync server to find the local IP address for my desktop PC where the syncing software is running. It appears this request is getting blocked, preventing the phone from finding the computer and thus making it unable to sync.

Any suggestions on how to get this to work? Thanks!

[dslr595148]

Q1 While we get that you have FIOS Internet, do you also have FIOS TV?

Please note for this next question even if you have another one that is not use, you must say so. For example: Yes, but it is a spare.

Q2 Do you have a separate router?

Please note for this next question: One of the NICs must be a wired NIC and it should not be a portable type of computer (ex: a laptop).

Q3 Do you have spare computer that works that either has two NICs or you could add a second NIC?

[ajwe · Accepted solution]

1. Yes, I have FIOS TV
2. I have my old FIOS G1100 router (unplugged, not in use)
3. I have another computer, but it’s in a location in the house where I can’t wire it up

Although I’m still interested in whether the G3100 has settings related to “DNS Rebind Protection” (for my own understanding), I was able to solve the specific problem I was having as follows:

• I changed the sync settings on my phone. Previously, it was set to call out to the AkrutoSync server to find the IP address of my PC. I changed the name of the server to instead use the local network name of my desktop and the router seems to have the IP available by that name (it’s shown in the DNS Server settings page in the router admin). So, instead of calling out to AkrutoSync, my phone asks for my local desktop (e.g., ‘OfficeDell’), gets the IP addr from the router, and then syncs up super-fast with my PC

So, at least for now I don’t need to try a more complicated setup with an extra computer involved (but thanks for considering that solution!).

[mstein80]

[mstein80]

advanced

..dns

....dnsserver

......Enable DNS Rebind Protection

Uncheck the box and apply changes.

I don't think the screenshot went through.