IPv6 Support

[bonomani]

Current IPv6 Status

1. Devmon and IPv6 Compatibility:

   • IPv6 Support: While IPv6 is not tested, the NET_SNMP_C and SNMP_session libraries used in Devmon do support IPv6. This suggests that Devmon can technically support IPv6 for SNMP communication.

2. Xymon and IPv6 Compatibility:

   • Untested: Xymon’s compatibility with IPv6 is untested, but it is expected to work with some adjustments.
   • Hosts File Format:
     • Xymon’s hosts.cfg file format should be compatible with IPv6. However, there is uncertainty around how Xymon handles the “0.0.0.0” IP in relation to IPv6 DNS resolution.
     • If the IP in the hosts file is 0.0.0.0, Xymon uses DNS resolution (via the c-ares library). The question arises whether the same logic applies to IPv6 addresses, like ::, for DNS resolution.
     • When the IP is specified (not 0.0.0.0), Xymon polls that IP directly and uses the hostname as a reference.
     • Xymon’s hosts file can act as an override for DNS resolution, but it’s not ideal for all scenarios, especially when reverse DNS (PTR) records are implemented.

3. DNS Override Considerations:

   • Internet: Overriding DNS can be useful to obscure information, preventing detailed knowledge about the network structure.
   • Internal Network: It may not always make sense to override DNS, as reverse DNS records are commonly used internally. The security benefits are less significant in such environments.
   • Efficiency: Overriding DNS can help quickly define monitoring before the real DNS entries are in place. However, this doesn’t effectively hide host or network details.
   • Compatibility: The hosts.cfg format is similar to the real hosts file, making it flexible but with some limitations.

4. Summary:

   • IPv6 in Devmon: IPv6 should work in Devmon since its SNMP libraries support it, though it’s untested.
   • Xymon IPv6: It is likely compatible with IPv6, but adjustments are needed in the hosts.cfg file format. There is some uncertainty about how DNS resolution will work for IPv6 addresses, specifically :: addresses.
   • DNS Overrides: Overriding DNS entries can be useful in some cases (especially for external networks), but it’s not always necessary or efficient for internal networks.

5. Pending Work:

   • Xymon IPv6 Implementation: The task of enabling IPv6 in Xymon is close to being completed but is not finished yet, and therefore, this subject is postponed for now.