Yes you can access the router's configuration pages without being connected to the internet. The link you quoted (converted to "click here") is contained within the router, it isn't located on the internet.
This thread is now locked and can not be replied to.
Best phone camera 2016/2017: Galaxy S7 vs iPhone 7 vs Google Pixel vs HTC 10 Evo vs OnePlus 3T vs…
1995-2015: How technology has changed the world in 20 years
These are the Best Christmas Ads and Studio Projects of 2016
Super Mario Run preview | Hands-on first impressions of Super Mario Run: Mario's iPhone & iPad…
Synology invites you to visit them at Insomnia on 26th – 29th August. Book your tickets now and visit Synology.