Outlook clients losing connection to Exchange 2003 server (intermittent and connected via VPN)
Hi,
We have got the following setup:
two offices, one in England and one in Scotland Both offices are connected via a VPN tunnel between two Sonicwalls All servers are in the England office, that includes the Exchange 2003 server and the DNS server (all servers are Server 2003)
There are four staff in the Scotland office, all got a wired connection to their SonicWall
The England office is connected to the internet through two DSL lines (slow as far away from the Exchange)
The Scottish office keep reporting that they are having problems with the connectivity to the Exchange server. I remote connected to one of their computers and noticed the following
I could ping the Exchange server and got a reply (via name and IP address) DNS seems to have been working fine (cleared the DNS cache on the laptop and tried again)
I could connect to all other network drives The VPN tunnel was active with no errors in the log All that time, Outlook was NOT connected and wouldn't connect to the Exchange server
All other staff in the Scotland office did NOT have a problem, it was only that one computer
Outlook clients are 2007 and 2010 so not client specific
This happens regularly but intermittently and never happens to the four staff at the same time (usually only one of them loses connection at a time). After about an hour or two Outlook just connects back up again and is working fine.
Nobody in the England office has ever reported any problems and a couple of people are using Outlook Anywhere and I haven't heard of any problems with that either (even though the issue might just not have happened, only introduced it last November and
not a lot of people are using it).
Does anybody have any clues as to where to look? We haven't got the best internet connection but this shouldn't cause such long connection problems, especially as I can ping the server and connect to the shares on it at the same time.
The only other problem they report is that they sometimes lose access to our Intranet (WSS 3.0 which is on a different server) - at the same time they have got access to all the shared folders though (again on a different server).
Any help would be much appreciated as the Exchange connectivity issue is more pressing than the SharePoint one - I don't know where to look anymore!
Many thanks
February 3rd, 2011 5:07pm
Outlook is pretty intolerant of such things, and it probably sensed high latency when it popped up the dialog. Cached mode is good for masking, though not eliminating, Outlook connectivity over slow links.Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."
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February 3rd, 2011 5:26pm
Hi Ed,
Many thanks for your reply - I already guessed it would be down to the connection but is it normal for it to stay disconnected for that length of time? Can anyone think of any setting that could improve this problem? As obviously they aren't happy about
this. They have got Cached mode but obviously can't send any emails during the time the connection is gone (or receive new ones) - OWA works during that time but isn't the most convenient solution.
(Yes, I know that our connection is anything else than ideal but saving money = no better solution for now...).
February 4th, 2011 4:45am
Hi,
it could be an mtu issue. Please try to ping the server from the clinet as follow:
ping your-server -f -l mtu_value
I assume your default mtu is 1500, in that case try to ping the server with that value. If you get a message stating you need to fragment the packets, try to lower the mtu_value to 1472, 1462, 1440, 1400 until you get a reply to ping as you're used
to see.
You would need to change the mtu size on your vpn endpoints to that value and packets going through the vpn will be fragmented with that size
hope it helps
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February 4th, 2011 6:55am
Hi,
it could be an mtu issue. Please try to ping the server from the clinet as follow:
ping your-server -f -l mtu_value
I assume your default mtu is 1500, in that case try to ping the server with that value. If you get a message stating you need to fragment the packets, try to lower the mtu_value to 1472, 1462, 1440, 1400 until you get a ping reply as you're used to see when
you use it without any option.
In that case you would need to change the mtu size on your vpn endpoints to that value and packets going through the vpn will be fragmented with that size
hope it helps
February 4th, 2011 6:55am
Thanks for this Vincenzo, I will give it a go on Monday.
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February 5th, 2011 7:41am
Hi Stefanie_R
Any update for your issue?
Hope it works!
Regards!
GavinPlease remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.
February 9th, 2011 3:53am
Hi Gavin,
Unfortunately I haven't been able to try this yet (one of our broadband lines has failed and as we were completely dependent on the second one I didn't want to make any changes) but I have just come across another thing today (by chance, as somebody in our
England office has had the same problem for the very first time).
"Download shared folders" was activated on all Exchange clients which I have not disconnected. I also found log entries on the Exchange server indicating that the maximum number of connections was exceeded, which would explain why Exchange stayed disconnected
for a while and then just reconnected again much later.
Strange enough, those event log errors have also appeared for people who have had no problems whatsoever, but I'm hoping that this might be the solution to this.
Will keep you updated - if there are no problems within 7 days it's probably resolved!
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February 10th, 2011 10:58am