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

Subject: Re: Channel Access problem over SSH
From: Andrew Johnson <anj@aps.anl.gov>
To: tech-talk@aps.anl.gov
Date: Tue, 17 Apr 2012 10:12:04 -0500
Hi Michael,

On 2012-04-17 michael.abbott@diamond.ac.uk wrote:
> From: tech-talk-bounces@aps.anl.gov [mailto:tech-talk-bounces@aps.anl.gov]
>  On Behalf Of Pavel Masloff
> 
> > Look. I have noticed that even when I am normally starting
> > an IOC on a linux machine, then I get these messages:
> > online_notify.c:CA beacon (send to "172.20.255.255:5065") error was
> > "Connection refused"
> 
> These messages are an old old chestnut and a pain in the bum.  We get them
> here all the time on our development network, and I understand that
> they're triggered by a misconfigured IOC somewhere on our network
> incorrectly responding to discovery packets (or something like that).  I
> would so much like to see the offending machine thrown in the bin, but
> apparently it's too hard to fix or something.

I started seeing these recently from vxWorks 6.8 and in looking further 
discovered how to enable them on Linux too.  I think we should change the way 
that the RSRV sends out beacon packets from calling connect() followed by 
send() to just calling sendto().  The former method allows us to detect ICMP 
returns, but it's starting to look like we don't really want to do that, 
especially since the error gets reported on a later use of that socket by 
which time we may have changed the address if we have more than one address in 
the EPICS_CA_ADDR_LIST or EPICS_CAS_BEACON_ADDR_LIST.

Any comments on that idea from the more network-savvy developers out there?

- Andrew
-- 
Never interrupt your enemy when he is making a mistake.
-- Napoleon Bonaparte

Replies:
RE: Channel Access problem over SSH Hill, Jeffrey O
References:
Channel Access problem over SSH Pavel Masloff
Re: Channel Access problem over SSH Pavel Masloff
RE: Channel Access problem over SSH michael.abbott

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