diff --git a/docs/ci-farm-lxc-setup.txt b/docs/ci-farm-lxc-setup.txt
index dd32950a07..6ed7a4ff54 100644
--- a/docs/ci-farm-lxc-setup.txt
+++ b/docs/ci-farm-lxc-setup.txt
@@ -26,6 +26,9 @@ Common preparations
     pairs, one per line (so one per container)
 *** `systemctl restart lxc-net` to apply config (is this needed after
     setup of containers too, to apply new items before booting them?)
+*** For troubleshooting, see `/var/lib/misc/dnsmasq.lxcbr0.leases`
+    (in some cases you may have to rename it away and reboot host to
+    fix IP address delegation)
 
 * Install qemu with its `/usr/bin/qemu-*-static` and registration in
   `/var/lib/binfmt`