Getting No Antenna bar when behind a NAT

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Asterisk Users 1 Comment

On Sat, Mar 19, 2011 at 2:10 AM, edward choi wrote:
> My Asterisk server is behind a NAT and I have set:
> —————————————————————————-
> externhost=”my.server.address”
> externrefresh=180
> localnet=
> localnet=
> localnet=
> nat=yes
> —————————————————————————
> in [general] section of sip.conf.
> I can make perfect conversation with my friend with the only exception of
> both parties being on private ip address.
> There can be four situations when a call is established.
> 1. A and B are not behind NATs
> 2. A is behind a NAT, but B is not.
> 3. A is not behind a NAT, but B is.
> 4. A and B are both behind NATs (different NAT of course).
> Among the four situations, 1, 2 and 3 works fine. (I guess externhost and
> localnet did the trick)
> But situation 4 does not work.
> In situation 4:
> When I call my friend, I get only one antenna bar with an exclamation mark.
> (I am not talking about the iPhone’s wifi bar, nor carrier’s bar. I am
> talking about Softphone’s bar). But my friend has no problem with the
> antenna bar. And both of us cannot hear anything.
> When he calls me, now he gets one antenna bar and an exclamation mark, but
> my antenna bar is just fine. And we still don’t hear anything.
> One time, there was only one time we could hear each other. He called me and
> for the first 3~4 seconds, we could hear nothing. But after that we could
> hear each other. I don’t know how it worked. It was just one random success.
> This is really weird. I tried Viber in the same situation and Viber works
> just fine every time.
> Could anyone give me any plausible explanation for this phenomenon?
> Ed

It shouldn’t matter but I would only define my actual network range
for localnet. What NAT/Firewall are you using in front of the Asterisk
box? I have had to turn off the NAT randomize port option or turn on
the NAT static port option. I have also sometimes had to disable the


One thought on - Getting No Antenna bar when behind a NAT

  • I am using a router called IPTIME n-604. It’s a famous Korean product.
    I have no firewall whatsoever but that ‘NAT randomize’ option is something
    I’ve never considered.
    I don’t even know if my router has such functionality, but I will definitely
    check on it.
    And I believe that my router doesn’t have built-in ALG functionality.

    I’ll narrow down the range of network for localnet and check the ‘NAT
    randomize’ option.
    Thanks for the info.


    2011/3/19 Ryan Wagoner