Working on a setup at the ATL office, November 2009
When I became System Administrator at the now-defunct E-Z Rent-A-Car, there was no WAN. Sites were using locally-setup routers without proper firewalling or rules in place: one site was even using public IPv4 addresses on workstations. It took several steps to mitigate this situation, given a limited budget + need to stabilize things.
Rental counter workstations were steadily migrated from XP-Home to Ubuntu-Linux installations.
During the Summer of 2007, several older computers were set up at remote sites to use as local caching and relaying for on-site units.
Programs were located to route critical IPv4 traffic over the IPv6 WAN, as needed. Concurrently, printers were migrated to IPv6-enabled Brother laser and MFC units.
Over the next year, on-site routers were replaced with ASUS WL-500g Premium units that ran OpenWRT. Over the next few years, tinc was combined with quagga and/or babel to maintain site-to-site connectivity. Spare routers were kept; that could be re-configured and mailed out with ease.
Around 2010-2011, a third party installed a Cisco-based phone solution with T-1 circuits. The local IPv4 networks were fully updated, and this network remained overlaid on that one.
This network remained active until at least 2013 (my departure from the company) and some time afterward. The company later merged with a competitor and folded during COVID.
A previous employer was trying to share resources between two sites on different continents. This was originally a Meraki setup with the same IPv4 subnet on both ends and a router-hosted VPN.
One site was migrated to an ARM-based router, running a Linux distribution and enabling IPv6 WAN access.
Another site was migrated to a similar router, but technical issues involving the ISP WAN access forced migration to an OPNsense VM on a PC-hosted Proxmox setup.
ZeroTier was deployed as an IPv4+IPv6 VPN solution for workstations and cloud VM resources.
Morro Data was deployed to provide cross-site cloud+local file storage.
A previous employer was attempting to provide for remote-work needs post-COVID.
Cloud resources were procured, and VMs created for different needs.
A WireGuard instance was created on a dedicated Linux VM. That VM was used to route IPv4 and IPv6 traffic between the other VMs (also on the VPN for logistical reasons) and off-site Windows users.
An old router was flashed with OpenWRT, and made into a one-armed router for linking the WireGard network with the LAN at the company HQ.
The on-site WAN was later updated to fiber-optic, and a PC-based OPNsense router was used to consolidate the functionality of the two older routers.
SAMBA installs in the cloud and on-site were used to manage user resources and DNS-based resource management.