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<== Date ==> <== Thread ==>

Subject: Re: Recsync: RecCeiver Server announcement contains Broadcast address instead of server ip address
From: Michael Davidsaver via Tech-talk <tech-talk at aps.anl.gov>
To: Heinz Junkes <junkes at fhi-berlin.mpg.de>
Cc: EPICS Tech Talk <tech-talk at aps.anl.gov>
Date: Sat, 23 Apr 2022 11:57:13 -0700
On 4/23/22 11:17, Heinz Junkes wrote:
Unfortunately, I don't understand it.

If one would stick to the intended protocol, then wouldn't it work to simply route the packet content with the server address in it into the subnet?

Yes.  As long as there is a reverse route for the IP source address.

Why is the server IP address not entered in the announcement server but '\xff\xff\xff\xff'?

Preferring the source address field in the IP header works better in the
presence of a firewall/router doing NAT.

...
     if(ntohl(buf->serverIP)==0xffffffff) {
         /* direct from the source */
         self->nameserv.ia.sin_addr = peer->ia.sin_addr;
     } else {
         /* proxied */
         self->nameserv.ia.sin_addr.s_addr = buf->serverIP;
     }
...
This is the logic.

References:
Recsync: RecCeiver Server announcement contains Broadcast address instead of server ip address Heinz Junkes via Tech-talk
Re: Recsync: RecCeiver Server announcement contains Broadcast address instead of server ip address Michael Davidsaver via Tech-talk
Re: Recsync: RecCeiver Server announcement contains Broadcast address instead of server ip address Heinz Junkes via Tech-talk

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