Sudden DNS issue with work VPN

[#1]

@pw23 reading this https://help.zscaler.com/zpa/what-zscaler-private-access it seems that Zscaler is not a true VPN in that it does not create a 'tunnel' to route all traffic to the remote network. Rather it routes something like policy based routing to direct ceratin traffic to the remote network.   

[#2 · Accepted solution]

That's right, I just learned this on a call this morning.

However, my issue has been solved.

I just had to specify a different public DNS in my router settings. So it would seem that indeed Plusnet's DNS doesn't resolve the IP address I need.

I went with Cloudflare's 1.1.1.1 DNS and everything's working fine now.

It was a glaringly obvious fix but I have no idea why Plusnet doesn't route...

Thanks to everyone that replied, you helped me learn quickly

[#3]

Out of interest...

Was your router previously set up with defined DNS servers? Or was it set to obtain its DNS servers automatically?

If the latter, then your desktop/laptop device would have been using your router as its DNS server (a common feature of home routers). Something that may not be common with 'hot spots'.

Dunno. Just one of the ideas/thoughts that floated through my remaining functional braincells. There was many possible causes (IMO).

[#4]

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@pw23 wrote:

It was a glaringly obvious fix but I have no idea why Plusnet doesn't route...

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Plusnet's DNS servers will only honour requests from Plusnet/BT IP ranges. If your work VPN is presenting a non-Plusnet IP then that would explain why DNS requests won't resolve. No idea why the VPN is falling back to the router for DNS mind you, rather than using a corporate server 🤷

[#5]

@bobpullen 

Good to see you around here - thank you for that little gem!!

[#6]

I think ultimately because it's a policy-based traffic-shaper in addition to a VPN?

The sites are actually public, but the internal DNS that I reached when using Zscaler wasn't in range, I suppose?

It's weird, but it's working again...