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Note: This column is part of a semi-regular feature that highlights current events in UIT's Network Services team.

Network News: Anycast DNS service available

IT administrators must migrate to new IP address by 11/30/18

By Jesse Drake

The University of Utah is making its Domain Name System (DNS) service more robust with a technology called Anycast. The Anycast Internet Protocol (IP) address 172.20.120.20 is available for U organizations to use. Several university organizations have already switched, and UIT's network team has been using and validating the new IP address for six months, according to Adam Hughes, UIT Network & Core Services technical supervisor.

IT administrators are asked to begin testing the IP address 172.20.120.20 as soon as possible to identify and resolve potential issues, and migrate well in advance of November 30, 2018.

After November 3, 2018, 172.20.120.20 will be the only IP address providing UIT DNS services, and DNS services will be retired from these IP addresses:

  • Campus: 155.97.136.200, 155.101.246.200
  • Hospital: 155.100.144.200, 155.100.69.200, 155.100.108.5, 155.100.69.3

From left, UIT Network & Core Services Engineers Florian Stellet
and Jesse Howerton, and Technical Supervisor Adam Hughes.

Users and clients not pointing to the new DNS Anycast address as their DNS server will lose functionality after November 30. External DNS architecture and functionality will not be affected. These DNS changes received approval from the university's IT Architecture & New Technology Committee on January 22, 2018.

The move to a single Anycast brings the university in line with current DNS industry standards, and provides greater network reliability and redundancy for DNS.

"DNS is definitely an unsung hero in connectivity," said Network Core Engineer Jesse Howerton.

Anycast is a "shared" IP address not local to any specific DNS server, instead allowing multiple machines to share the same IP address. When a request is sent to an Anycast IP address, routers direct it to the nearest available DNS server. Anycast architecture consists of five servers at various geographic and networking locations, providing ample failover tolerance.

"If something were to go wrong with a single device, we can just take it out of production, because we have four other servers that can easily handle the load," said Network Core Engineer Florian Stellet, noting that load is about 8,000 queries per second. "It doesn't matter what happens, DNS will be available."

This is part of broader effort by the network team to get a better handle on available IP space across all devices, stabilize the university's IP address management environment, and open up disaster recovery capabilities. Infoblox, UIT's management solution for IPs, DNS and Dynamic Host Configuration Protocol (DHCP), also employs security tools that better protect users from malware and malicious traffic.

If you have any questions, or would like guidance in testing a particular system with Anycast, your local IT support staff may be able to assist, or you may contact the UIT Help Desk at 801-581-4000 option 1.

Last Updated: 4/9/19