Every server has an imaging NIC (static, the only one that serves
DHCP/TFTP/HTTP boot/SMB) and a GE corporate NIC (DHCP client, SSH and the
webapp on 9009). The playbook guessed the PXE NIC and the installer put
172.16.9.1/24 on every en* NIC, so a two-NIC box could answer on the GE
network.
- New per-site vars pxe_nic_mac / corp_nic_mac (required, from
playbook/site-vars.yml or -e; template site-vars.example.yml), stable
names pxe_nic_name / corp_nic_name (default pxe0 / corp0, overridable),
pxe_server_ip, pxe_subnet, DHCP range. pxe_imaging_mac / pxe_ge_mac are
derived from them. The play stops before touching anything if a MAC is
unset, malformed, duplicated or not on the box (lists the box's NICs).
- Heuristic NIC detection and the single-NIC netplan task replaced by a
two-NIC netplan template (match macaddress + set-name), installed by
pxe-netplan-apply.sh: validate in a scratch root, back up, generate,
rename, apply, restore the previous config on any failure. cloud-init
network config disabled so it cannot rewrite it.
- dnsmasq: /etc/dnsmasq.d/pxe-nic-only.conf from the vars (interface=,
except-interface=, no-dhcp-interface=); dnsmasq.conf IP/range from vars.
- UFW per interface: imaging NIC 22, 67/udp, 69/udp, 80, 4433, 445, 139,
137/udp, 138/udp, 9009; GE NIC 22 and 9009 only. Old any-interface rules
and the stale 9011 rule removed after the new ones are in.
- sysctl drop-in: IPv4/IPv6 forwarding off; ip_nonlocal_bind so Apache
can bind the imaging IP before the address is up.
- Samba [global]: interfaces = 127.0.0.0/8 <imaging NIC>, bind interfaces
only. Apache 80 and 4433 on the imaging IP only; 9009 stays on all (TODO:
the webapp has no auth).
- autoinstall: DHCP only on en*, no static 172.16.9.1; apt geoip off and
offline-install fallback now that the corp NIC may have a lease.
- Blancco UEFI/Secure Boot: blancco_kver (7.0.0-34-generic) drives the
kernel, initramfs and modules builds instead of the running kernel;
outputs vmlinuz-ubuntu-70, kexec-initrd-70.img, kmod-<kver>.tar.gz as the
menu and blancco-init.sh expect; creates: guards keyed on the full kver.
Ubuntu's shimx64.efi.signed published as blancco/shimx64.efi.
download-packages.sh adds shim-signed, linux-generic-hwe-24.04 and the
pinned linux-image/modules/modules-extra for BLANCCO_KVER.
Rendered with the live MACs and names, netplan generate output is
identical to the live config; pxe-nic-only.conf and the Samba binding
match live directive for directive.
pxe-nic-check classifies each NIC from what it hears: LLDP/CDP/802.1X
from managed switches, foreign DHCP offers and their domain (one
DHCPDISCOVER on the imaging NIC; the GE NIC's networkd lease is read
instead), STP and ARP hosts for information. A kernel BPF filter keeps
bulk SMB traffic out of the capture loop; bridge ports are listened on
too, since LLDP and EAPOL stop at the port.
- dnsmasq drop-in runs --guard as ExecStartPre: exit 1 on a ge or
foreign-dhcp imaging verdict, fail open (loudly) on bugs or no link
- pxe-nic-check.timer runs --watch every 5 min: stops dnsmasq on a bad
imaging verdict, never starts it
- /run/pxe-nic-status.json (0644, atomic) for the webapp
- playbook installs it all and writes /etc/pxe-server/nic.conf from
pxe_imaging_mac, pxe_ge_mac, pxe_corp_domain_suffixes,
pxe_nic_allowed_switches
- unit tests plus a no-root network-namespace lab (veth pairs, a raw
socket DHCP/LLDP peer and real dnsmasq); docs/pxe-nic-guard.md has the
operator notes and the two floor tests
