bosh-dns fails to resolve FQDN associated with many IP addresses in Operations Manager

Products

• Operations Manager

Issue/Introduction

When attempting to resolve a fully qualified domain name (FQDN) from within an app container, it fails with the error message: 

connection timed out; no servers could be reached

The DNS resolution succeeds on first attempt but fails on subsequent tries because of a problem with the cache handler.

The problematic FQDN maps to numerous IP addresses (20+) such that response payload is greater than 512 bytes.

For example:

 $ nslookup fqdn.example.com  

name: fqdn.example.com
address: 10.###.###.## 

name: fqdn.example.com
address: 10.###.###.## 
 ...
name: fqdn.example.com
address: 10.###.###.## 
 
$ nslookup fqdn.example.com  
connection timed out; no servers could be reached

Environment

Product Version: 2.5

Resolution

This is a known issue with bosh-dns. The issue is that bosh-dns cache handler does not handle TC/EDNS properly.

The recommended resolution is to upgrade bosh-dns to 1.16 or higher. The latest patched releases of Operations (Ops) Manager 2.6, 2.7, 2.8+ contains the bosh-dns release with the fix for this issue. Upgrading to the latest patch of any of these releases will resolve the issue.