On 10/12/17 00:48, Patrick O'Callaghan wrote:
On Wed, 2017-10-11 at 21:24 +0800, Ed Greshko wrote:
> On 10/11/17 20:26, Patrick O'Callaghan wrote:
>> I installed the above kernel this morning and immediately experienced
>> very noticeable delays in accessing websites (2 or 3 seconds each
>> time), apparently caused by slow DNS lookups. The same happened when
>> running a 'ping' from the Shell, so I don't think the browser
(Chrome)
>> is to blame.
>>
>> Rebooting with 4.13.4-200.fc26.x86_64 fixed the problem immediately.
>>
>> Anyone else notice this?
> Examples of the sites you've tried? Whose DNS server are you using? If your
ISP,
> can you change to 8.8.8.8 (google's servers)?
Popular sites such as
www.nytimes.com and
www.theguardian.com. I took a
look at my router's config and saw that its DNS setting was set to
"dynamic". I assume that means uPnP or DHCP but I don't know where it
was pointing at. I changed it to 8.8.8.8 and 8.8.4.4 and rebooted the
new kernel. It seems to have improved but I'll keep an eye on it.
Unless your router uses odd terminology Dynamic DNS, or DDNS, isn't what you think it
is.
DDNS is a way to register your router's IP address in the DNS if it changes.
Meaning if your router gets its IP address via DHCP from your ISP DDNS will update
the DNS to reflect the change. This way if you are outside your LAN you can always
use a name to get the IP address of your router and connect to it or (via port
forwarding) devices on your LAN even if the IP address of your router changes.
So, in your configuration it sounds like your Fedora system is getting all the
network configuration from your router. So, if you look in /etc/resolv.conf you see
the IP address of your router? Yes?
I don't see how a change of kernel could have affected this, unless
there's some subtlety in uPnP (or DHCP), but we'll see.
I don't think you're seeing any kernel issues.
Anyway, in my network I have various DNS configurations for different reasons.
I have a caching nameserver running on one system. I have another system configured
to point to my router which uses a proxy DNS provided by my VPN service. And another
system which is configured to directly contact Google's servers.
All are running just fine and queries all happen in milliseconds.
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