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DNS Host not resolving FQDN slack-core.com

Thierry Brasse1 over 4 years ago

Hello all,

I need help resolve an issue.

on UTM 9 I've created a Network Definition -> DNS Host to resolve the FQDN slack-core.com. It says "unresolved"

I've tried slack.com it resolved perfectly.

slack-core.com does exist. But for some reason the UTM is unable to resolve it.

Does anyone have an idea what could be the issue? My DNS servers works properly.

Thanks a lot.

Cheers,

Thierry.

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0 Jaydeep over 4 years ago

Hi Thierry Brasse1

I checked and found that slack-core.com is not resolved on public DNS servers. If you have configured a DNS host of this in your Internal DNS server and you want UTM to resolve it from there, please create a DNS request route using this KBA: Sophos UTM: Best practices for DNS Configuration

Regards

Jaydeep
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0 Thierry Brasse1 over 4 years ago in reply to Jaydeep

Hello Jaydeep,

slack-core.com is a public facing domain name.

See the screenshot below. For some reason the Sophos UTM is unable to resolve it. Could it be the format of the FQDN?
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0 Jaydeep over 4 years ago in reply to Thierry Brasse1

Again, not sure where you're able to resolve this. I've checked with Google's DNS as well but it doesn't get resolved.

Regards

Jaydeep
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0 Thierry Brasse1 over 4 years ago in reply to Jaydeep

Google is also resolving the FQDN :(
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0 BAlfson over 4 years ago

Salut Thierry and welcome to the UTM Community!

There's a little confusion here. There is no A-record for the FQDN slack-core.com, so there is no name resolution possible. The domain slack-core.com exists, but none of the name servers listed for it supplies an IP for the domain name used as an FQDN.

My guess is that some criminals created that domain to try to defraud people while holding themselves out as Slack Technologies, but Slack found out about it and captured the domain. The clue is the SPF record for slack-core.com - no email from that domain is to be treated as valid.

Cheers - Bob

Sophos UTM Community Moderator
Sophos Certified Architect - UTM
Sophos Certified Engineer - XG
Gold Solution Partner since 2005

MediaSoft, Inc. USA
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