sonicwall to Exchange

I have problem on sonicwall NAT to Exchange,

Through some Telco provider from some clients, it works. but some doea not

for those that cannot work, ir xan ping oe telnet to 443

any idea
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yo_beeDirector of Information TechnologyCommented:
Are they resolving the correct Public address?
Sounds like a DNS issue.  Users that this is not working are you able to troubleshoot the device with some PINGs or NSLOOKUP for resolution to the address vs IP?
NetExpert Network Solutions Pte LtdTechnical SpecialistCommented:
Since the clients are able to ping and telnet to exchange server, NAT and firewall policies are working.

Suspecting that there could be DNS issue on the client side?

Or, you can check DNS firewall policies on the sonicwall

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AXISHKAuthor Commented:
ping the Exchange and it return with right IP address....
Check your load balancing.   You might have it set for failover and it is responding on the wrong one at times.
AXISHKAuthor Commented:
Thx. A link in a Ethernet channel has problem. Replace and fix everything.
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