[Zope-dev] [ZEO] protocol problem

[Leonardo Rochael Almeida]

On Mon, 2002-02-25 at 05:44, Dieter Maurer wrote:
> [...]
> 
> We use Zope 2.5 together with ZEO 1.0b5 and there seems to be
> a problem with the communication between Zope and ZEO.
> 
>   Several times a day, Zope reports that it has been disconnected form
>   storage (a warning), that it tries to reconnect but fails
>   due to "error 131, 'Connection reset by peer'".

If your ZEO Client (ZC) is behind a masquerading firewall or other NAT
(with your ZEO Server (ZS) on the other side, obviously) you might be
getting a timeout from your firewall. If the ZC doesn't communicate with
the ZS for some time, the masquerading firewall might lose track of the
connection and when the ZC finally sends some data, the firewall sends
back an ICMP packet to the effect: 'Connection reset by peer' because it
doesn't know what the ZC is talking about.
> 
>   ZEO on the other hand reports that it had opened the connection
>   and keeps it open until Zope stops.

The ZS will never know about the closed connection because (I believe)
it only sends data closely after the ZC sends data (so the firewall
knows the connection and won't complain).

If this is the case, you might want to increase the timeout on your
firewall or find a way to make the ZC talk to the ZS regularly so as to
keep the connection alive (it would be ideal if the ZEO protocol had a
keep-alive or PING or noop command that could be regularly sent down the
wire).

-- 
Ideas don't stay in some minds very long because they don't like
solitary confinement.