Issues Receiving Mail After Brief Connection Loss

Ok, we've been having a ton of problems at our office with our Verizon DSL connection. Verizon tech support has been less than helpful. Their big solution was to downgrade our connection speed to 1.5 Mbps try to maintain a more stable connection, since we are almost the max distance away from their central station, and evidently are on a fairly noisy line. This did not work, even when we were supplied with a new modem. Before this recent issue, we hadn't really had any connection problems in about a year.

Our internet connection continues to drop for short periods. The big issue is, when it comes back, we have access to the internet, and our SBS 2003 server's web functions (OWA, RWW, SharePoint) can be reached from the internet, but inbound connections to our SMTP virtual server time out. The only way to open email back up is to reboot our WatchGuard FireBox (hardware firewall) through its configuration page. This will restore email delivery until our next drop, after which, I will need to restart the FireBox again, and it goes on and on in this fashion.

Any thoughts? Is the Firebox possibily going bad? If that was the case, wouldn't we have issues with more than just email after the connection was restored?
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Sceler85Asked:
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Sceler85Connect With a Mentor Author Commented:
replaced the firewall, and my suspicions were correct. no further issues observed.
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Sceler85Author Commented:
I should add that we can send email via our exchange server while not being able to receive.
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Steven WellsSystems AdministratorCommented:
This problem could be caused by high latency on your link. There are mx tools on the internet where you can enter your domain name and the website will connect to your exchange server and give you a report on how long it takes to connect.  
SMTP is pretty robust protocol but if there are high ping times some exchange servers will time out when trying to connect.  I suspect there could be a problem with your internet connection such as phone line problems etc.
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Sceler85Author Commented:
Any idea why rebooting the hardware firewall helps?
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Steven WellsSystems AdministratorCommented:
No idea sorry. does the firewall do any smtp functions or does it just port forward?  I would probably disable any smtp functions and let email pass through without any inspection etc. Give that a go for a while and see if that helps.
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Sceler85Author Commented:
It's only port forwarding to our mail server, there are no additional SMTP functions handled by the firewall.
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Sceler85Author Commented:
Well, after we lose connectivity, I've seem timeouts after 25 and 30 seconds from inbound mail server tests. Once I reboot the firewall, the tests run with no problem, until the next connection drop. Any other ideas? It's possible that this is mostly Verizon's fault, but I'm looking for all the help I can get.
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Steven WellsConnect With a Mentor Systems AdministratorCommented:
perhaps it takes long to re-establish sync with your internet connection and the reboot does a force. From memory some routers/modems have a setting to ensure auto resync.
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