blueSIP supports ENUM. When the number you are trying to call has an ENUM entry with reachable SIP address, a connection free of charge will be made to this SIP address. For blueSIP telephone numbers, an automatic ENUM entry for your blueSIP SIP address is created automatically.

blueSIP uses e164.arpa service. Lookups will be made in e164.arpa only.

All telephone numbers that start with +49 800 are as well reachable and free of charge via the PSTN gateway.