SIP Alg on netgear routers

[albgen]

Hello,

i have an IP Phone which does not recieve calls if the SIP Alg feature is enabled!!!
Disabling it my ip phone can recieve calls!
why it mess all when its switchen on?

[Jack_]

Post in the subforum that refers to your specific type of router. According to external site info, only the following consumer Netgear devices support SIP Alg: WGR614v9 Wireless-G Router and DGN2000 Wireless-N ADSL2+ Modem Router Firmware V1.0.18_8.0.9NA

[jmizoguchi]

and few Prosafe routers has SIP ALG support

[albgen]

This feature not only dont work, but it adds trouble to the sip protocol!!!!!
I have a Netgear DG834N. On the lan side, is installed a sip hardware phone and on the the computer i have installed a client software sip.
On both(hardware and software sip), if the "sip alg" feature is enabled i cant recieve calls! Instead, if "sip alg" is disabled then i can recieve calls.

ps:there are no problems on outgoing calls.

[jmizoguchi]

albgen wrote:

This feature not only dont work, but it adds trouble to the sip protocol!!!!! I have a Netgear DG834N. On the lan side, is installed a sip hardware phone and on the the computer i have installed a client software sip. On both(hardware and software sip), if the "sip alg" feature is enabled i cant recieve calls! Instead, if "sip alg" is disabled then i can recieve calls. ps:there are no problems on outgoing calls.

you could put IP Phone on DMZ side of the routers.

[albgen]

maybe fixing the firmware router could be e a better solution than exposing my ip phones on the dmz

[jmizoguchi]

albgen wrote:
maybe fixing the firmware router could be e a better solution than exposing my ip phones on the dmz

I don't see huge issues putting IP phone on DMZ but bug in a firmware should be fixed

also in Prosafe Routers, few new firmware add way to disable SIP ALG in command line as well.

report your finding by opening the case
https://my.netgear-support.com/myNETGEAR/ENG/login.asp

[kittykaos]

SIP ALG was initially created to rewrite SIP packets on SIP port 5060 for the purpose of bypassing NAT and to not be as intrusive to the WAN network. Unfortunately, the rewriting of the packets can really cause problems especially since most VoIP providers have a system for SIP traffic that coincides with the SIP ALG. Basically, SIP ALG is bad and you want to do everything you can to bypass it and you can do one of 2 things (or both) 1) Disable SIP ALG in your router and 2) ensure your SIP Port is NOT on 5060. 5062 is what I use.

Also, make sure you are not double Natting. If you have a gateway AND an additional router, you are going to experience dropped calls and one-way audio. Your best bet is to only use a modem/router combo, or have your gateway bridged if you insist on an additional router.

Hope this helps.