Weird DNS resolution issue
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@Pete-S said in Weird DNS resolution issue:
All requests from the LAN will originate from the routers WAN IP address so it will be the same IP from the DNS servers point of view. In other words, it's unlikely it's some problem on the DNS servers.
Right - which is why it was so weird why some machines got DNS responses and some did not.
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@Pete-S said in Weird DNS resolution issue:
@Dashrender said in Weird DNS resolution issue:
Was there something else I should have tried?
When troubleshooting you can make DNS queries to specific DNS servers that doesn't use the clients DHCP originated default DNS servers.
For example:
nslookup mangolassi.it 8.8.8.8or
nslookup mangolassi.it 8.8.4.4It would be better than just pinging.
Nice - thanks didn't know that.
I did all the ipconfig stuff - no change... at least not until I change the DNS in the DHCP server.
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@Dashrender said in Weird DNS resolution issue:
@Pete-S said in Weird DNS resolution issue:
@Dashrender said in Weird DNS resolution issue:
Was there something else I should have tried?
When troubleshooting you can make DNS queries to specific DNS servers that doesn't use the clients DHCP originated default DNS servers.
For example:
nslookup mangolassi.it 8.8.8.8or
nslookup mangolassi.it 8.8.4.4It would be better than just pinging.
Nice - thanks didn't know that.
Well, I don't do it often enough so I always forget how to do it and then I have to look it up...everytime....
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@Dashrender said in Weird DNS resolution issue:
Anyone heard of an issue like this? where a DNS provider seemingly blocks some requests from a given IP, but not others?
It happens. Can be based on a lot of factors. Can also happen from your router.
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@Pete-S said in Weird DNS resolution issue:
All requests from the LAN will originate from the routers WAN IP address so it will be the same IP from the DNS servers point of view. In other words, it's unlikely it's some problem on the DNS servers.
Right, it's far more likely to be UDP flooding on a per client basis.
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@Dashrender said in Weird DNS resolution issue:
@Pete-S said in Weird DNS resolution issue:
All requests from the LAN will originate from the routers WAN IP address so it will be the same IP from the DNS servers point of view. In other words, it's unlikely it's some problem on the DNS servers.
Right - which is why it was so weird why some machines got DNS responses and some did not.
Unlikely, but still possible. Keep in mind that each machine on your network gets its own session. And each session can be on a different server on the DNS provider's end. So it might have been different servers that they were reaching.
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@Pete-S said in Weird DNS resolution issue:
I usually let the router act as a DNS forwarder or resolver and cache.
Always this.
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@JaredBusch said in Weird DNS resolution issue:
@Pete-S said in Weird DNS resolution issue:
I usually let the router act as a DNS forwarder or resolver and cache.
Always this.
meh - 6 of one!
I suppose it's possible that would have resolved this specific issue as the router would have been the only device making connections to the external DNS... but then again - it could have caused all machines to go without DNS when the upstream server stopped responding...
I didn't dig into the acient TP link router they had - they didn't want me to replace it with the newer Netgear they had once I got it working.
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@Dashrender said in Weird DNS resolution issue:
I suppose it's possible that would have resolved this specific issue as the router would have been the only device making connections to the external DNS... but then again - it could have caused all machines to go without DNS when the upstream server stopped responding...
Not very likely. Plausible, but not likely enough to avoid it.
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@scottalanmiller said in Weird DNS resolution issue:
@Dashrender said in Weird DNS resolution issue:
I suppose it's possible that would have resolved this specific issue as the router would have been the only device making connections to the external DNS... but then again - it could have caused all machines to go without DNS when the upstream server stopped responding...
Not very likely. Plausible, but not likely enough to avoid it.
sure - but then again, I've never seen this situation before either - so I would have previously called it unlikely.
