On 26/09/2020 12:14, Harry Bloomfield wrote:
I originally had several items on my LAN, with fixed IP's configured
within the devices themselves, such as an IP cam, routers and printers.
Everything else relied on the router's DHCP to allocate an IP, when they
connected.
As time as passed and my LAN has become busy with things connected, some
things have been unable (despite there being unused addresses), to be
allocated an address without a reboot (laptops). I recently added 8x
It might be that the router has them allocated to other MAC addresses
and the lease has not yet expired.
On networks with lots of devices connecting and disconnecting it can
make sense to lower the DHCP lease time to allow addresses allocated to
now dormant devices to be re-used sooner.
Smart Plugs, which exacerbated the problem, so I thought to try setting
up almost everything without a fixed IP, a router allocated IP's.
My main router, which connects to FTTC is runs OpenWRT, which does not
allow a reserved section of IP's for static addresses. Rather it seems
to use a sort of intelligent reserve, where it DHCP allocates above the
static IP's.
Have you made sure that you have no fixed IPs set in your DHCP pool?
Typically you want the router to say start allocating DHCP addresses
from 192.168.x.100, with a pool of say 100 addresses, then make sure
that all static devices are in the 192.168.x.2 - 192.168.x.99 or
192.168.x.201 - 192.168.x.254 range.
Coming to the question now....
I have now set every item which connects to my LAN, either with an IP in
the device, or a static address in my router. No more issues with
laptops failing to acquire an IP after waking. One thing I have also
noticed, is that my IP cam's frame rate has rocketed. It is specified as
25fps, prior to the above changes it would manage around 2 to 5 fps. It
now manages 10 to 18fps depending on the picture content.
The IP cam connects to my main OpenWRT router, that is wire connected to
a second router, the second router connects via wifi to my laptop, which
is what I am viewing the IP cam on. Why should the fps suddenly improve?
It sounds like you had an IP address conflict before.
Sometimes having a quick peak at the PCs ARP table can tell you
interesting stuff:
arp -a
You can then lookup the cached mac addresses[1] and see whether they
actually correspond to the manufacturer of the device you were expecting
(and also whether they stay consistent or flip between macs).
[1] Various web sites like:
http://www.coffer.com/mac_find/
https://macvendors.com/
For example, taking a snippet from the results on one of my machines I get:
C:\Users\Johnarp -a
Interface: 192.168.1.13 --- 0x3
Internet Address Physical Address Type
192.168.1.1 00-1d-aa-71-71-48 dynamic
192.168.1.2 00-50-7f-f1-1a-32 dynamic
192.168.1.4 f4-ec-38-aa-28-a8 dynamic
192.168.1.10 24-5e-be-04-e4-18 dynamic
192.168.1.11 00-18-dd-23-22-3c dynamic
192.168.1.12 38-2c-4a-bc-58-e3 dynamic
(note that the "dynamic" reported here is just indicating that the
address has not been specified as static on the PC itself - its not a
reflection of if they are actually dynamic addresses on the network)
Which if you look em up shows, Draytek, Draytek, TP-Link, QNAP, Silicon
Dust Engineering, ASUSTek Computer Inc
Also has your second router got its DHCP server enabled? You only want
one DHCP server active per subnet, or otherwise there is a danger of
address conflicts unless you have carefully set them up to allocate
addresses from non overlapping pools, and also outside the range used
for any static IPs.
--
Cheers,
John.
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