Question about Sockets

  • Thread starter Thread starter Bernd
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Bernd

hi,

is it possible to use a Socket (proto_udp) and recieve icmp messages ?
what i want to do is, send a datagram to a remote host/port and check if
the host replies with port_unreachable (i think icmp type 3).
is this possible with a udp Socket and the RecieveFrom() method ?.
another approach would be (at least thats what i think) to use a raw
socket with proto_udp.
is this a wrong way to go ?

thanks
 
Bernd said:
hi,

is it possible to use a Socket (proto_udp) and recieve icmp messages ?
what i want to do is, send a datagram to a remote host/port and check if
the host replies with port_unreachable (i think icmp type 3).
is this possible with a udp Socket and the RecieveFrom() method ?.
another approach would be (at least thats what i think) to use a raw
socket with proto_udp.
is this a wrong way to go ?

thanks
Click to expand...

Hi,

hhmmm, I think ICMP messages are not sent through UDP. So, I'm not sure
but I think its not possible to do that with a UDP Socket.

Yours sincerely

Andy
 
Andy said:
Hi,

hhmmm, I think ICMP messages are not sent through UDP. So, I'm not sure
but I think its not possible to do that with a UDP Socket.

Yours sincerely

Andy
Click to expand...


ok, thanks for your answer. and yes you are right, icmp is not sent
through udp.
would it be possible to work with 2 sockets ? lets say i create an udp
socket, send a dgram and recieve the reply with a raw socket
proto_type_icmp ?

thanks
 
Bernd said:
ok, thanks for your answer. and yes you are right, icmp is not sent
through udp.
would it be possible to work with 2 sockets ? lets say i create an udp
socket, send a dgram and recieve the reply with a raw socket
proto_type_icmp ?

thanks
Click to expand...

Hi,

ok, I've looked in W. Richard Stevens book "TCP/IP Volume 1" and found
out, that you can use the UDP Socket to receive the ICMP reply of your
sent datagram. In the ICMP message the IP-Header and the first 8 bytes
of the IP-Data are transmitted. And Stevens wrote: the ICMP module can
assiciate with this information an UDP Port and respectivly a process
with the ICMP reply.

Yours sincerely

Andy
 
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