When you connect to a VPN server, your IP address is replaced with the server's IP. To the school or office firewall, it looks like you are visiting the VPN's site rather than Tumblr.
Sometimes, network blocks are implemented at the DNS (Domain Name System) level. When you type "tumblr.com," your network's DNS server simply refuses to look up the IP address. unblock tumblr
A web proxy acts as an intermediary between you and the internet. You visit the proxy site, type in Tumblr’s URL, and the proxy site displays the content for you. This hides your browsing activity from the local network firewall. When you connect to a VPN server, your