Re: no UDP traffic (from MS Exchange) on internal side of firewal l

[David Dinin <DDinin_(_at_)_resourcecapitalgroup_(_dot_)_com>]

Au contraire, mon ami.  Exchange Server does use UDP packets to notify
clients of new mail... in keeping with their usual style, however, Microsoft
only documents these things in their troubleshooting articles and not in the
actual product specs or manuals:

http://support.microsoft.com/default.aspx?scid=kb;EN-US;264035
(Not the sort of thing you'd ordinarily run across unless you were
specifically looking for it... they do keep this stuff well-hidden :)

And yes, all the clients are on the same 10.0.0.0/24 subnet as the server...
that's why this is so perplexing.  The UDP packets clearly are not reaching
the client for some reason, and if they're not getting eaten by the
firewall, then where are they going?  Does Exchange need local DNS to run
properly?  I would think it would keep track of active client connections
using either straight IP addresses, or WINS, both of which are working just
fine.  

And although I don't want to run a DNS server on the firewall/NAT box, I may
be forced into it by other concerns anyway.  I would still like to know why
my UDP packets aren't arriving, though.  That's why I sent this in; I
figured that maybe some more experienced eyes than mine might spot some
stupid error in pf.conf, which certainly seemed straightforward enough to
set up (but hey, everybody makes mistakes).

Thanks for your time and efforts!  I'm sure I'll get it fixed soon,

   -d


-----Original Message-----
From: Lars Hansson
To: misc_(_at_)_openbsd_(_dot_)_org
Sent: 1/29/03 9:58 PM
Subject: Re: no UDP traffic (from MS Exchange) on internal side of firewall

On Wed, 29 Jan 2003 21:21:42 -0500
David Dinin <DDinin_(_at_)_resourcecapitalgroup_(_dot_)_com> wrote:

>  See, Exchange uses UDP packets to inform LAN clients that they
> have mail so that the clients can then open TCP connections to
retrieve
> their mailboxes,

No it's not, at least not according to the official docs.
It could use MS-RPC but that's not using UDP and nowhere does it say it
uses
it to notify clients of new mail.

>  and the local clients are not receiving them; therefore, no
> one in our office gets new mail until they close and reopen a folder
(Inbox,
> Sent, whatever, as long as the mailbox has to refresh).

They have to poll the server every X minutes.

> The firewall is static IP'd at 10.0.0.1, the mail server is static
IP'd at
> 10.0.0.2 (at presently also serving the web page), and everyone else
is on
> DHCP.

So you're saying that the clients are also on 10.0.0.*? Then it
certainly has
nothing to do with the firewall.

---
Lars Hansson