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Outbound SMTP is blocked by SonicWall

Posted on 2015-02-12
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Last Modified: 2015-02-17
Having a strange problem.  We have a SonicWall TZ200 with WAN failover set up between Comcast and AT&T DSL.  The SonicWall is blocking outbound SMTP traffic on port 25 but only when both Internet connections are connected.  If I disconnect either connection, the traffic goes out.  As soon as I connect both, SMTP traffic is blocked but everything else goes out.  There are not access rules set up from LAN to WAN except for the default rule that allows all traffic.  I know it's the SonicWall because it works when I connect a computer directly to Comcast or DSL.  The other strange thing is that we had a T1 connected prior to upgrading to Comcast and it worked fine.  Scratching my head on this one.  Any ideas?
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Question by:dhoose
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by:tmoore1962
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Make sure Sonic wall is in failover and not load balance.  Check this article out for more assistance https://support.software.dell.com/kb/sw7497
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by:dhoose
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It is set up as basic failover without load balancing, although I did try turning load balancing on to see if that would fix it but it didn't.  That article is for incoming mail but I'm only having problem with outbound.
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dhoose earned 0 total points
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I found the problem.  There was an entry in routing that was set to only go to the primary connection.  I don't know how it got there or why but I deleted it and now everything works.
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by:dhoose
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I found the solution myself.  Weird issue.
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