I have a soho LAN with a gateway server running isc-dhcpd-server and bind9 on one NIC for the LAN & wifi.

The client connects to the LAN but often can't see the server on even to ping it.

I can see the client sets up its IP address with DHCP and on some clients e.g. the mac laptop, /etc/resolv.conf contains the correct name-server entry.

On my linux laptop, when it's not connecting, the resolv.conf entry is not correct.

At some point from a minute to 30 mins later, the client will suddenly connect and for a while all will be fine.

Meanwhile the internet connection on the gateway server is consistently OK.

Here's the server's dhcpd.conf:

subnet netmask {
  option subnet-mask;
  option domain-search "localdomain";
  option domain-name-servers;
  option routers;

log-facility local7;
default-lease-time 600;
max-lease-time 7200;
option domain-name "localdomain";
option domain-name-servers gondolin.localdomain;
ddns-updates on;
ignore client-updates;
update-static-leases on;
ddns-update-style standard;
update-optimization off;

include "/etc/dhcp/ddns-keys/rndc.key";
# must be same as "/etc/bind/rndc.key";

zone localdomain. {
     key "rndc-key";

zone 0.168.192.in-addr.arpa. {
     key "rndc-key";

gondolin.localdomain is the gateway hostname.

I'm not getting any errors in /var/log/dhcpd.log and the lease entries in /var/lib/dhcp/dhcpd.leases look like this:

lease {
  starts 0 2019/11/03 18:00:35;
  ends 0 2019/11/03 20:00:35;
  cltt 0 2019/11/03 18:00:35;
  binding state active;
  next binding state free;
  rewind binding state free;
  hardware ethernet 24:5b:a7:20:26:a2;
  uid "\001$[\247 &\242";
  set ddns-rev-name = "";
  set ddns-dhcid = "\000\001\001x\341c*8-]\267\336\210;3d$\376#\203\273P\207\002\375=\3327\035[\241\307\262\374/";
  set ddns-fwd-name = "Sylvies-iPhone.localdomain";
  client-hostname "Sylvies-iPhone";

I can't find any errors on the gateway server, nor on the clients in ubuntu /var/log/syslog or iOS /var/log/system.log files.


Turns out it was just the wifi access point. I did a power cycle and it was all fine.

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