On Thu, 2017-10-12 at 05:55 +0800, Ed Greshko wrote:
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
> > > 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
> > can you change to 22.214.171.124 (google's servers)?
> Popular sites such as www.nytimes.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 126.96.36.199 and 188.8.131.52 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
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.
I know what DDNS is. That's not what I'm talking about. I'm not using
DDNS at present though I have done in the past. The router has a
control panel for configuring *its own* DNS resolver, i.e. where it
forwards queries to upstream. It was set to "dynamic", which I
interpret to mean "get the configuration from the ISP". (The broadband
connection is PPPoE so it presumably behaves like an Ethernet).
Changing it to explicitly point at Google is what had the desired
effect. It now seems likely that the kernel version was mere
coincidence, at least I hope so.
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.
As I say, that may well be the case (I hope it is). The router config
change seems to have corrected the problem for now.