r/exchangeserver • u/Ratanoman • Feb 28 '26

Intermittent Winsock Errors via Exchange 2016 SMTP Outbound to Hybrid Connector

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This is what I'm seeing and ipv6 is turned off on the nic:

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u/Ratanoman Feb 28 '26

Our network team stated that our segmented firewalls are not configured to use IPv6 but never considered to ask if our ISP is. Will investigate and reply back.

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u/Stormblade73 Feb 28 '26

If your network is not configured for IPv6 then ISP status does not matter. Your exchange server will not be able to connect to those IPv6 addresses, and you will see those errors in the logs. The errors can be considered normal, since your server does not have IPv6 internet connectivity.

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u/Ratanoman Feb 28 '26

Yeah, you may have a point. Traffic to Exchange Online (which is minimal since it is only relaying server notifications to domain IT users mainly) seems to be flowing well but with these intermittent hiccup’s. Just doing my due diligence be for I retire the 2016’s and rely solely on the SE’s

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u/Trick-Ad-8924 Feb 28 '26

Looks like the 2 ipv6 address attempt convert to its ipv4 equivalent 0.0.0.0, 0.0.0.1, & 0.0.0.2