DSL-AC68U - Latest Official Firmware and SIP Problems

[SpaceCoyote]

In a nutshell, I recently upgraded my firmware to 3.0.0.4.380_3281 from 3.0.0.4.378_9212 and now I am unable to receive inbound calls on my SIP softphone.

I upgraded because of some odd-looking activity in my logs (people trying to login remotely), and after seeing the change log for the current version I thought it was time to upgrade.

In 378_9212, I had WAN > NAT Passthrough > SIP Passthrough disabled - everything worked fine
In 380_3281 if I use the same setting, my phone won't register. With SIP Passthrough enabled, the phone registers and I can make outbound calls, but inbound just goes straight to voicemail.

I did a full router reset after upgrading.

AFAIK, the soft phone uses SIP-standard ports (5060) and I have UPnP enabled. Just unsure why I can't take inbound calls.

Any help would be great. Thanks.

 

[SpaceCoyote]

Hmmm. I've got it working, but I don't see how changing what I changed would make any difference.

I've allocated the PC that has the softphone a fixed IP.
Upgrade the softphone software to latest version.
Rebooted my PC

Incoming calls now work.

I'll have to keep an eye on it.

 

[fax]

Also consider that a full router reset to defaults and manual insert of settings (no file restore of settings) is recommended when moving between major firmware revisions (ie. from 378 to 380)

 

[SpaceCoyote]

Also consider that a full router reset to defaults and manual insert of settings (no file restore of settings) is recommended when moving between major firmware revisions (ie. from 378 to 380)

Thanks for the note. But yeah, much as it pains me, I do hard reset and re-enter the router config manually.

 

[RMerlin]

In 378_9212, I had WAN > NAT Passthrough > SIP Passthrough disabled - everything worked fine
In 380_3281 if I use the same setting, my phone won't register. With SIP Passthrough enabled, the phone registers and I can make outbound calls, but inbound just goes straight to voicemail.

In recent firmware releases, Asus decided to block port 5060 if you have Passthrough disabled. It forces SIP users to enable the passthrough. Unfortunately, it means that if the NAT helper is interfering with your smartphone/PBX, you have no way to work around it beside sticking with an older firmware, or switching to a custom firmware.

 

[SpaceCoyote]

In recent firmware releases, Asus decided to block port 5060 if you have Passthrough disabled. It forces SIP users to enable the passthrough. Unfortunately, it means that if the NAT helper is interfering with your smartphone/PBX, you have no way to work around it beside sticking with an older firmware, or switching to a custom firmware.

That makes a lot of sense, and explains what's going on. Thank you.

I think I have everything working properly now with the current firmware, but if it causes any more issues in the future I might consider getting a separate modem and an RT-AC68U so I can use custom firmware.

 

[SpaceCoyote]

Okay, so I've been testing my inbound VoIP calls over the last two days and their success is intermitant on 380_3281.

If I downgrade to 378_9212 are there any threats I need to be aware of?

EDIT: I've found a "workaround" but I'm not sure I want to be doing this every morning.

1. Disconnect my VoIP client
2. Disable SIP passthrough
3. Re-enable SIP passthrough
4. Reconnect my VoIP client I can take inbound calls.

Edit 2: I've spoken with ASUS, and they've confirmed that this "bug" will be passed to the developers for review. But I wonder if the blocking of port 5060 when SIP Passthrough is disabled is a feature

 

[pcwizard7]

Hello I m having the same issue as you not being able to receive calls now you mention a workaround and to go back to previous Firmware which seems the easiest way to fix the issue until they have a fix in next firmware.

Now F/W 3.0.0.4.378.9313 is available to download for Router only version and was made around the same time as DSL version 378_9212 do you think it has the bug in it?

what would be latest firmware that shouldn't have the issue? as none of change-logs talk about SIP type stuff

thanks

 

[Josh T]

Hi all. I have the latest firmware and can confirm I have this issue. It seems that the problem is when you make an update to routing SIP gets blocked. So I find this happens when I do things like login a VPN or update a service. I haven't verified if this happens on startup since this modem is so rock solid I haven't experienced it yet!

In any event I have tracked down the issue to a port trigger in /tmp/filter_rules. As I have the DSL version I don't have access to all the fancy script triggers because I can't install Merlin firmware. But due to USB hack I can set up a task to run every minute and do things. I've added to my script to remove this trigger if found. So worst case is I'll get a blip for up to a minute. I'm running it now and will see how it goes. This is what I'm running each minute:

iptables --delete FORWARD -p udp -m udp --dport 5060 -j TRIGGER --trigger-type out --trigger-proto udp --trigger-match 5060 --trigger-relate 5060

If you have Merlin firmware just add this to your firewall-start or nat-start (sorry I don't know which one). If you are like me you will need to setup a hack to initiate a cron job. If anyone has any other ideas of something to change to fix this let me know. I would love to find away to do something similar like Merlin firmware.