Dynamic dns for public ip address of the firewall – Kerio Tech Firewall6 User Manual
Page 118
Chapter 8
Configuration of network services
118
8.3 Dynamic DNS for public IP address of the firewall
Kerio WinRoute Firewall provides (among others) services for remote access from the Internet
to the local network (VPN server — see chapter
and the Clientless SSL-VPN interface — see
chapter
). Also other services can be accessible from the Internet — e.g. the WinRoute’s web
interface (see chapter
), remote administration of WinRoute by the Administration Console
(see chapter
) or any other service (e.g. web server in local network — see chapter
These services are available at the firewall’s public IP address (i.e. public IP address of the
WinRoute host). If this IP address is static and there exists a corresponding DNS record for it,
a corresponding name can be used for access to a given service (e.g. server.company.com).
If there is no corresponding DNS record, it is necessary to remember the firewall’s IP address
and use it for access to all services. If the public IP address is dynamic (i.e. it changes), it is
extremely difficult or even impossible to connect to these services from the Internet.
This problem is solved by WinRoute’s support for dynamic DNS. Dynamic DNS provides DNS
record for a specific name of a server which will always keep the current IP address. This
method thus allows making mapped services always available under the same server name,
regardless of the fact if IP address changes and how often.
How cooperation with dynamic DNS works
Dynamic DNS (DDNS) is a service providing automatic update of IP address in DNS record for
the particular host name. Typically, two versions of DDNS are available:
•
free — user can choose from several second level domains (e.g.
no-ip.org
,
ddns.info
,
etc.)
and
select
a
free
host
name
for
the
domain
(e.g.
company.ddns.info
).
•
paid service — user registers their own domain (e.g. company.com) and the service
provider then provides DNS server for this domain with the option of automatic up-
date of records.
User of the service gets an account which is used for access authentication (this will guarantee
that only authorized users can update DNS records. Update is performed via secured connec-
tion (typically HTTPS) to make sure that the traffic cannot be tapped. Dynamic DNS records
can be updated either manually by the user or (mostly) by a specialized software — WinRoute
in this case.
If WinRoute enables cooperation with dynamic DNS, a request for update of the IP address
in dynamic DNS is sent upon any change of the Internet interface’s IP address (including
switching between primary and secondary Internet connection — see chapter
). This keeps
DNS record for the particular IP address up-to-date and mapped services may be accessed by
the corresponding host name.
Note:
1.
Usage of DDNS follows conditions of the particular provider.