[KB3526] How to enter an IPv6 address for your mirror server


  • You cannot enter the IPv6 address in hexadecimal format separated with colons
  • "Could not connect to server" error


In Microsoft Windows operating systems, IPv4 addresses are valid location identifiers in uniform naming convention (UNC) path names. Unfortunately, the colon, which is used in IPv6 addresses written in hexadecimal format, is an illegal character in a UNC path name. As a result, the use of IPv6 addresses is also illegal in UNC path names. Microsoft implemented a transcription algorithm to represent an IPv6 address in the form that can be used in UNC path names.

For more detailed information how to configure client workstations with ESET products installed to access the mirror server, read our Knowledgebase article.

Configure a mirror server with an IPv6 address

  1. Use the Microsoft transcription algorithm to convert the IPv6 address to a literal address (for use in your ESET product). 

    For example, the IPv6 address


    will be transcribed as follows:

  2. Open the ESET product which is to serve as the mirror. Press the F5 key to access Advanced setup, expand Update, and then click GeneralEdit. Enter your transcribed IPv6 address (created in step 1) into the Update servers field and click Add OK. Your address should be entered in one of the following formats:

    http://xxxx-xxxx-xxxx-xxxx-xxxx-xxxx-xxxx-xxxx.ipv6-literal.net:2221 (IPv6)


    http://[IPv6 address]:2221 (IPv6)

Using this format

Addresses using this format will be automatically resolved by Microsoft software without any queries to DNS name server.