SIP Extensions and loss of Internet connection

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Asterisk Users 7 Comments

Hi all!

A few days I have problems connecting to the Internet on my house and
since then my local SIP extensions are no longer registered against the
local Asterisk server.

I’m using Asterisk I was researching on the Internet and I
found that it can be related to a bug of chan_sip, can it be? In this
case, is there a possible workaround?

Thanks in advance for your reply.


7 thoughts on - SIP Extensions and loss of Internet connection

  • Hi, Phil.

    The /etc/resolv.conf of the host on which I installed Asterisk points to
    an internal DNS. Is there a parameter in the Asterisk configuration
    where also I have to “force” the use of an internal DNS server?

    Thanks for your reply.


  • The extensions have configured the Asterisk server by its IP, so I do
    not think there is a problem on that side.

    To enable debug I should use ‘sip set debug’? from the Asterisk CLI? I
    do not see any record in the CLI after running this command. However,
    from Twinkle, for example, I see the following:

  • You have to be a bit more specific. For example is your Asterisk box
    behind a router/nat? Or does your asterisk box have two NICs one for
    the public and/or natted IP and one for the LAN? You need to specify
    your exact setup.

    It’s probably not a bug. Maybe you are registering by name and the
    name resolves to the public IP, and if you are in a DSL cable
    connection you public IP will change and perhaps you don’t even have a
    public IP. Another possibility is that your ISP does not in fact give
    you public IPs (like most in the USA) and you have your LAN in the
    same network definition as theirs. I mean there are so many
    possibilities but you need to specifiy the exact network setup (IPs,
    masks, routing, etc.)

  • Hi, Alejandro.

    Asterisk is not behind the router. The problem I’m having is in the LAN.

    As I told Phil, I am experiencing the same problem both from a softphone
    on a workstation with fixed IP as a Grandstream phone (which gets
    network configuration via DHCP). In both extensions, the Asterisk server
    is configured with IP, so in that sense, I don’t think the server is
    inaccessible to customers.

    On the other hand, I made sure to have commented in the sip.conf file
    any reference to providers such as Ekiga or iptel, so the server
    should not be trying to get to the Internet.

    It would appear that the server for some reason was ‘locked’. For
    example, when I try to register from Twinkle softphone, I get the

  • […]

    I have had a similar problem when we have some sort of network
    disruption, but it _never_ affects clients on the LAN, it only affects
    my SIP registrations on the public network. I have 2 NICs one on the
    public network with a public IP (but dynamic), and one on the LAN. I
    also have a cron to a dyndns service that updates the name of this
    server so other PBX can register to it.

    Anyway, sometimes, but very rare, something happens and the is no way
    that it re-registers to external SIP sources, and no other external
    SIP can register with it either. Nothing works except to reboot the
    server a-la Windoze. I have Asterisk 1.6 on FreeBSD 8. I have always
    attributed this problem to my set-up or a quirky NIC but maybe it’s
    related to your problem (although it has _never_ happened to us in the
    LAN extensions). Unable to find a solution, and since it’s really very
    rare, we have test calls every day to make sure everything is working

    Alejandro Imass