Hello,
I’m trying to do my discovery protocol (like the Digi’s ADDP), I send an UDP multicast packet (on 224.0.5.128).
If the pc and the Digi are on the same subnet all work fine, but when the they are on different subnets I can receive my multicast UDP packet but when I try to send a reply, the Digi starts to look for the gateway and after 5 attempts it fails.
An example from Wireshark:
10.118.1.249 is the pc
192.168.1.8 is the Digi
192.168.1.1 is the Digi’s gateway
This is the Digi ADDP discovery (it works on different subnets):
source | dest | protocol | info
(the ADDP discovery packet)
10.118.1.249 | 224.0.5.128 | UDP | Source port: gpfs Destination port: digiman
(here it looks for the gateway 3 times)
Digiboar_4c:c7:f2 | Broadcast | ARP | Who has 192.168.1.1? Tell 0.0.0.0
Digiboar_4c:c7:f2 | Broadcast | ARP | Who has 192.168.1.1? Tell 0.0.0.0
Digiboar_4c:c7:f2 | Broadcast | ARP | Who has 192.168.1.1? Tell 0.0.0.0
(then it sends the discovery reply)
192.168.1.8 | 10.118.1.249 | UDP | Source port: digiman Destination port: gpfs
This is my discovery:
source | dest | protocol | info
(the discovery packet, it is received correctly)
10.118.1.249 | 224.0.5.128 | UDP | Source port: 51611 Destination port: qadmifevent
(here it looks for the gateway 5 times then quits the sendto )
Digiboar_4c:cb:19 | Broadcast | ARP | Who has 192.168.1.1? Tell 192.168.1.8
Digiboar_4c:cb:19 | Broadcast | ARP | Who has 192.168.1.1? Tell 192.168.1.8
Digiboar_4c:cb:19 | Broadcast | ARP | Who has 192.168.1.1? Tell 192.168.1.8
Digiboar_4c:cb:19 | Broadcast | ARP | Who has 192.168.1.1? Tell 192.168.1.8
Digiboar_4c:cb:19 | Broadcast | ARP | Who has 192.168.1.1? Tell 192.168.1.8
Is there a way to send an UDP packet without searching the gateway?
(and why the ADDP ARPs have 0.0.0.0 as ip address?)
Thank you