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Network blocks

Traffic from certain ports may be temporarily blocked to protect against malicious network activity. A block is applied if:

  • the IP address is sending a large volume of spam emails;
  • complaints are received regarding the IP address;
  • the IP address is found in DNSBL spam lists — public blacklists for IP addresses and domains;
  • The IP address is blocked at the request of the local regulator .

You can view such blocks in the control panel. If you have eliminated the cause of the block, you can submit an unblocking request. Each request is reviewed individually, and we do not guarantee a positive response.

Also, some TCP/UDP ports and access to some internet resources are blocked by default. For more information, see the Blocked ports and internet resources instructions.

View network locks

  1. In the control panel, in the top menu, click Products and select Network incidents.

  2. Open the Network blocks tab. For each block, the socket and protocol, blocking period, and action on traffic that falls under the blocking conditions are indicated:

    • discard — traffic is blocked completely;
    • redirect — traffic is redirected to an additional scrubbing system;
    • rate limit — traffic bandwidth is limited to the specified value (bytes per second).

  3. If the IP address is not displayed in the locks, but traffic is limited:

    3.1. Make sure that the port is not blocked by default. We block certain ports for Servercore infrastructure security. For more information, see the Blocked ports and internet resources instructions.

    3.2. Make sure that the IP address is not blocked due to a DDoS attack. For more information, see the Blocked attacks instructions.

    3.3. Check if the IP address is listed in spam blacklists on the mxtoolbox website. If the IP address is in spam blacklists, submit an unblocking request.

    3.4. If the IP address is not blocked and is not in spam blacklists, but traffic is restricted, create a ticket.

    3.5. Wait for a Servercore engineer to respond with the reasons for the block.

Submit a request for unblocking

Each unblocking request is reviewed individually; we do not guarantee a positive outcome.

  1. Create a ticket. In the ticket, specify:

    • the port that needs to be unblocked;

    • purpose of port usage. If you plan to use the port for mailing, specify the type of mailing, the number of emails in the mailing, a sample email, and whether the recipient can opt out of the mailing;

    • the IP address for which the port needs to be unblocked.

  2. Wait for a response in the ticket from a Servercore engineer regarding the steps to take for unblocking.

    If the port was blocked due to the IP address being included in a spam list, we will request its removal. We cannot guarantee the result — spam lists are managed by third-party services, and they decide on removal independently.

  3. Resolve the cause of the block and report it in the ticket.

  4. Wait for a response in the ticket from a Servercore engineer regarding the decision.