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Network settings

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Opening SMTP Ports

For security reasons, outgoing TCP ports (25,24,2525, 387, 465, and 587) and UDP port (5060) are blocked by default on all VPS servers. This is to prevent the sending of spam. To remove the block, follow the steps below:

  1. Spell out the domain zone. The A record of the domain must necessarily refer to the IP address of your server in HOSTKEY.

  2. Send a request to technical support specifying the purpose for which you need to open outgoing SMTP ports and the address of the domain from which (or a subdomain of) it is being using.


    We reserve the right to ask you additional questions about the domain name and your options for using it.

  3. After analyzing the domain name, we will make a decision about opening ports for SMTP operation and inform you.

Are any other network ports blocked?

To protect client equipment from unauthorised use by third parties, we block all incoming traffic to the following ports:

1. NTP

Block source and destination addresses with UDP NTP.

There is one NTP server in each site:

  • NL: -;
  • US: -


  • 137/TCP,UDP - NETBIOS-NS (NetBIOS Name Service);
  • 138/TCP,UDP - NETBIOS-DGM (NetBIOS Datagram Service);
  • 139/TCP,UDP - NETBIOS-SSN (NetBIOS Session Service).

3. TCP/UDP 11211

  • TCP 11211;
  • UDP 11211.


  • 19/TCP,UDP.


  • 111/TCP,UDP.

6. Microsoft SSDP. Allows you to discover UPnP devices.

  • 1900/UDP.

7. Smart Install Service (Cisco)

  • 4786 /TCP.


These ports can be used by attackers for DDoS attacks. If you need to use these ports, please contact us and we will open them.

How can I configure PTR records?

Login to the service control panel.

Go to the control panel for a specific server - tab Network - and click on the (IP settings and DNS RTP management) icon.

Which DNS can I use for my server?

ou can use public cashing DNS-servers, for example, Google public DNS servers (IPs and

How can I remove the bandwidth restriction caused by exceeding the traffic limit?

If the bandwidth limit of your dedicated server has been exceeded, the connection speed of the server concerned will be restricted to 10 Mbps. You will receive warning messages via email prior to reaching the limit.


100Mbps or 1Gbps speed can be optionally restored by committing to pay the overspent traffic invoices, which will be automatically generated by the system based on the consumption of the prepaid traffic. The basis for calculation is for prevalent traffic only.

If you have any questions, please, contact us.

Is it possible to request an additional static ip address?

Additional addresses can be ordered by sending an email to [email protected] or by creating a ticket in your account. Prices for single addresses and blocks are indicated on our website.

Why doesn't my server's IP match its location?

Free location services often contain outdated or wrong data. Checking IP should be done using the RIPE service, which serves the allocation of addresses in Europe. The search form is on the first page of the service. You can always check the location of the server using the traceroute command.

Why my Internet speed is lower than it should be?

Lower Internet speed can occur for several reasons outside HOSTKEY's area of responsibility, for example:

  • Hardware or software issues — check the condition of the network equipment, make sure the correct drivers are used and verify that the software used does not affect network availability (possible malware/viruses or the use of software that is not mandatory but is “eating up” network resources).
  • The physical distance to the server and the status of network related operators — the further you are from the server, the weaker the signal strength may be. The access speed is judged in relation to HOSTKEY’s network. Issues with the connectivity to the networks of other providers (of higher level or local operators) can also lead to poor connection, meaning if you rent a server with 1 Gbps channel but test the speed from an overloaded network or from a network with a capacity of 100 Mbps, from a technical point of view, the HOSTKEY staff won’t be able to solve the problem.
  • Traffic shaping — please, check whether or not you have received a system notification from us regarding exceeding prepaid traffic. In this case there was an automatic traffic shaping and you would have been informed.
  • etc.


In order to identify possible problems on HOSTKEY’s side and to research optimal solution, please, provide connectivity test results from ping and traceroute commands. You can do it here.


Please, note: to get more accurate information it is recommended to do a few tests using both commands.

After the completion of the tests, please, email the screenshots to our Support for examination. Use the email address registered in your client information with HOSTKEY.