If your network is blocking Sumdog, you may have issues accessing it.
If your network uses content filtering, your IT administrator may need to allow Sumdog to pass those filters automatically. He or she can do this by whitelisting "*.sumdog.com", or an equivalent.
Whitelisting means the server's filters will never block content from that site. We make sure that all of our public-facing servers have an alias in the sumdog.com domain, or its subdomains. Whitelisting any servers whose domain ends in .sumdog.com will let you access all of our content. Everything you will need to use Sumdog comes from a sumdog.com subdomain.
It's best not to whitelist an IP address for Sumdog, as we may change these, to help Sumdog respond more quickly to its users.