Is it possible, bind has done but the OS still respond with ICMP destination unreachable

Hi,

I encounter a problem seems strange. I ran ser(a open source SIP
server) which binds to the port 5060. After the system starting up, I
can see aparently that the ser has successfully bind to UDP 5060. But
when other machine send packets to 5060(UDP), the OS responds it with
ICMP error(destination unreachable, port unreachable), any other
possibilities will cause this?

I am using ubuntu 6.10.

Thanks in advance.

abai

On 3ÔÂ27ÈÕ, ÉÏÎç10ʱ20·Ö, "Bin Chen" <binary.c...@gmail.com> wrote:
> Hi,
>
> I encounter a problem seems strange. I ran ser(a open source SIP
> server) which binds to the port 5060. After the system starting up, I
> can see aparently that the ser has successfully bind to UDP 5060. But
> when other machine send packets to 5060(UDP), the OS responds it with
> ICMP error(destination unreachable, port unreachable), any other
> possibilities will cause this?
>
> I am using ubuntu 6.10.
>
> Thanks in advance.
>
> abai

If a program first does a bind, and then it enter a dead loop, will
the OS find the binder has dead and respond a ICMP error?

> I encounter a problem seems strange. I ran ser(a open source SIP
> server) which binds to the port 5060. After the system starting up, I
> can see aparently that the ser has successfully bind to UDP 5060.

You shouldn't be saying "apparently". Run netstat -ltu and see what it
*has* bound to.

On Mar 28, 9:18 am, Allen McIntosh <nos...@mouse-potato.com> wrote:
> > I encounter a problem seems strange. I ran ser(a open source SIP
> > server) which binds to the port 5060. After the system starting up, I
> > can see aparently that the ser has successfully bind to UDP 5060.
>
> You shouldn't be saying "apparently". Run netstat -ltu and see what it
> *has* bound to.

Sure, I have checked this and see the binding.