ASUS RT-N56U and RT-N66U


This device from Asus does not have a firewall which masks the contact address of SIP packets. This means that SIP traffic and RTP traffic pass through without interference and should work with OnSIP without issue.

If there is a SIP ALG running, telnet into the device and enter the following commands:

nvram get nf_sip

(It should return a "1")
nvram set nf_sip=0
nvram commit

Then reboot the router for the changes to take effect.



Certain firmware can cause disabling SIP ALG to stop all SIP traffic. It is a bug in the router software. This is the case with their firmware version  With the latest firmware, it's recommended to leave SIP ALG enabled.

For phones to pick up the change immediately, reboot each of them, otherwise they will pick up the new NAT table with changes during their next registration.


NOTE: The information provided above is from another OnSIP customer offering these settings for other customers with a similar device. OnSIP does not sell nor monitor equipment and/or it’s firmware updates/etc. The settings of routers can change and are out of the control of OnSIP. For best results, reach out to the manufacturer directly.


Optimize your network for business VoIP with the right router

Download Business Routers Guide

Was this article helpful?
0 out of 0 found this helpful