--- metadata: - name: generator content: Diplodoc Platform v5.66.0 alternate: - https://admin.contest.yandex.ru/docs/en/contest/restrict-access.md - https://admin.contest.yandex.ru/docs/ru/contest/restrict-access.md - href: https://admin.contest.yandex.ru/docs/en/contest/restrict-access.md type: text/markdown title: Markdown version - href: https://admin.contest.yandex.ru/docs/en/llms.txt?revision=ae2dc943804b31ca2a40bdf90c0b2d0f82206b48 rel: describedby --- > **Documentation Index:** Fetch the complete configuration index at https://admin.contest.yandex.ru/docs/en/llms.txt?revision=ae2dc943804b31ca2a40bdf90c0b2d0f82206b48 # Internet access To host an offline programming contest, you need conditions that: - Ensure fairness and equal opportunities for participants. - Prevent plagiarism and cheating. - Support the contest rules and regulations. Restricting internet access at the contest venue can help. An internet ban is not always appropriate. At training or educational events, access to external resources, documentation, APIs, and tools can help participants. Internet access is also relevant to contests held entirely online. If you need to restrict access, explain the reason and include the restriction in the rules to avoid confusion among participants. {% note warning %} All contests with restricted internet access must use the domains for [internal users](https://admin.contest.yandex.ru/docs/en/users.md#internal): - [int.contest.yandex.com](https://int.contest.yandex.com) for the new participant interface. - [official.contest.yandex.com](https://official.contest.yandex.com) for the classic participant interface. Only internal users can access these contests. {% endnote %} The administrator interface is available only through [admin.contest.yandex.ru](https://admin.contest.yandex.ru) with a Yandex ID account. The organizers responsible for the contest must therefore retain internet access. ## Restrict internet access Yandex Contest needs access to specific domains and IP addresses. Use the list below to configure the network so participants can access only the required resources. {% cut "Yandex Contest IP addresses and domains" %} #| || **Domain** | **IPv4 addresses** | **IPv6 addresses** || || int.contest.yandex.ru int.contest.yandex.com official.contest.yandex.ru official.contest.yandex.com assets.contest.yandex.net | 87.250.251.40 | 2a02:6b8::29f || || clck.yandex.ru clck.yandex.com | 77.88.21.14 87.250.250.14 87.250.251.14 93.158.134.14 213.180.193.14 213.180.204.14 | 2a02:6b8::14 || || yastatic.net yandex.st | 37.9.64.225 178.154.131.215 178.154.131.216 178.154.131.217 | 2a02:6b8:20::215 2a02:6b8:23::225 || || contest-problem-files.s3-private.mds.yandex.net contest-hidden.s3-private.mds.yandex.net contest-public.s3-private.mds.yandex.net | 87.250.251.158 | 2a02:6b8::3:158 || || mc.yandex.ru | 77.88.21.119 87.250.250.119 87.250.251.119 93.158.134.119 | 2a02:6b8::1:119 || |# {% endcut %} If you host a contest with restricted internet access on a subdomain other than `official` or `int`, contact [Support](https://admin.contest.yandex.ru/docs/en/troubleshooting.md) for an up-to-date list of addresses to use for blocking. ### Open the required ports Allow outgoing HTTP and HTTPS connections to the listed resources (TCP ports 80 and 443). Also allow access to your DHCP server (UDP ports 67 and 68) and DNS servers (UDP port 53). ### Block other internet access You can restrict internet access in these ways: 1. **Filter by IP address and domain name.** Configure access to specific IP addresses and domain names on your network equipment or proxy server. Many routers support IP filtering. Consult the device manual or manufacturer's website for instructions. These settings are usually under **Firewall**, **Access control**, or **IP filter** in the router menu. 2. **Use a proxy server.** Configure a proxy server. If you don't have one, you can use [Squid](https://www.squid-cache.org/) to control internet access. Set up an [allowlist](https://wiki.squid-cache.org/SquidFaq/SquidAcl) of domain names and configure all computers to use the proxy. Make sure participants can't disable it in their browser settings. For example, block direct internet access for all devices on your network except the proxy server. {% note warning %} Do not filter by domain name alone using SNI or a DNS server. {% endnote %} If neither method is suitable, restrict access on each participant's computer. ### Prevent access through other Wi-Fi networks If the computers have Wi-Fi adapters, prevent participants from accessing the internet through other networks, such as a phone hotspot. - If you use a wired connection, disable the Wi-Fi adapter in Windows Device Manager. - If devices connect through Wi-Fi and the router blocks internet access, allow them to connect only to your Wi-Fi network. For example, on Windows, run these commands in a command prompt as an administrator: `netsh wlan add filter permission=allow ssid="YourNetwork" networktype=infrastructure` `netsh wlan add filter permission=denyall networktype=infrastructure` The first command allows a connection to `YourNetwork`; the second hides all other networks. Replace `YourNetwork` with the name of your network. To remove the filter, run: `netsh wlan delete filter permission=denyall networktype=infrastructure` `netsh wlan delete filter permission=allow ssid="YourNetwork" networktype=infrastructure` Write to Support