the_prg_server_configuration_old/nix-system-configs/old-server-notes.md

Old Server Notes

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Gateway WAN Configuration - Essential Info

Network Details

WAN IP:           130.225.91.242/27
Netmask:          255.255.255.224
Gateway:          130.225.91.225
Gateway MAC:      f0:7f:06:98:4a:64
Network:          130.225.91.224/27
Broadcast:        130.225.91.255
Interface:        ens18
MTU:              1500
Domain:           prg.dtu.dk
Hostname:         prg-lan-gateway
FQDN:             prg-lan-gateway.prg.dtu.dk

Upstream Path

Gateway (130.225.91.225) → Cisco e11_0-1.bg106.internet.i3.cisco.net.local
Next Hop (192.38.93.34) → DTU edge router et2_12.90.sb-1g303-1

Interface Configuration

Interface:        ens18
Type:             Static IPv4
Address:          130.225.91.242/27
Gateway:          130.225.91.225
No VLANs, No PPPoE, No MAC cloning

Proxmox VM Configuration

VM ID:            100
Node:             ve0
Memory:           2GB
CPU:              2 cores (1 socket)
Disk:             10GB (local-lvm)
NIC Model:        VirtIO

Network Devices:
  net0 (ens18):   virtio=2A:99:D6:03:DD:92,bridge=vmbr1  ← WAN
  net1 (ens19):   virtio=0E:27:6A:11:A0:77,bridge=vmbr0  ← LAN
  net2 (ens20):   virtio=42:D7:85:15:E1:FF,bridge=vmbr2  ← LAN

DNS Servers

Primary:          1.1.1.1 (Cloudflare)
Secondary:        8.8.8.8 (Google)
Tertiary:         130.225.89.2 (DTU)
Domain:           prg.dtu.dk
Search:           prg.dtu.dk

NTP Servers

time.cloudflare.com

Firewall Rules

NAT (Outbound)

Chain: POSTROUTING
Action: Masquerade all traffic on interface ens18

Filter (Inbound)

Accept: Loopback (lo)
Accept: Established/Related connections
Drop: All other traffic from ens18 (WAN)
Default: Accept (for other interfaces)

Port Forwarding

None configured

System Requirements

IP Forwarding:                      Enabled (net.ipv4.ip_forward=1)
Reverse Path Filtering:             Enabled (net.ipv4.conf.all.rp_filter=1)
SYN Cookies:                        Enabled (net.ipv4.tcp_syncookies=1)
Accept ICMP Redirects:              Disabled (net.ipv4.conf.all.accept_redirects=0)
Send ICMP Redirects:                Disabled (net.ipv4.conf.all.send_redirects=0)
Accept Source Route:                Disabled (net.ipv4.conf.all.accept_source_route=0)
Log Martian Packets:                Enabled (net.ipv4.conf.all.log_martians=1)
Ignore Broadcast Pings:             Enabled (net.ipv4.icmp_echo_ignore_broadcasts=1)
Ignore Bogus ICMP Errors:           Enabled (net.ipv4.icmp_ignore_bogus_error_responses=1)

Hosts File

127.0.0.1       localhost
130.225.91.242  prg-lan-gateway.prg.dtu.dk  prg-lan-gateway
::1             localhost ip6-localhost ip6-loopback
ff02::1         ip6-allnodes
ff02::2         ip6-allrouters

LAN Interfaces

ens19:            10.123.123.1/24, 192.168.0.1/24 (dual IP)
ens20:            10.255.255.1/24

Critical Notes

Platform:         Proxmox VM (node ve0, VM ID 100)
WAN MAC:          2A:99:D6:03:DD:92 (must preserve for rebuild maybe, due to DTU being very thorough maybe)
WAN Bridge:       vmbr1 (not vmbr0)
IPv6:             Not configured