Reporting: Unbound DNS¶
Starting from OPNsense 23.1, users are able to gain insight into DNS traffic passing through their Unbound DNS resolver using the reporting tool under.
All data presented here is kept on the system for a total of 7 days, creating a rolling window into DNS traffic without allowing the system to take up boundless storage space.
The overview tab shows high-level DNS traffic data.
The total amount of queries Unbound has handled, starting from the moment as reported above the counters. This will either be from the moment the gathering of statistics has been enabled, or up until the last 7 days. Keep in mind that the counter is as seen from the incoming side, and will increase regardless of the type of response returned.
The amount of queries Unbound has successfully resolved. This counter does not distinguish between forwards or recursion, and excludes every other response type, such as responses from cache, local-data or a local policy such as a blocklist.
The amount of queries Unbound has blocked. This is either because a queried domain was part of a blocklist, or part of a user-configured exact match as configured in.
The size of the current blocklist (if any). This will equal the total amount of domains listed inside all the active blocklists.
Every query counter shows the percentage as part of to the total amount of queries.
Adding up both the blocked and resolved queries does not equal the total amount, since the amount of responses from cache, local-data and other possible sources such as Unbound itself on e.g. a SERVFAIL are not shown.
Also included in the report are two DNS traffic graphs, the first one being the query graph, and the second one being the client graph. Both graphs show the amount of incoming queries over a selectable span of time. The query graph also shows the amount of blocked queries. You can hover over the dots in the client graph to see which client it is, as well as the amount of queries associated with this client. If you proceed to click on this point of data, you will be referred to the Details grid containing every query within this time interval made by this client.
Both the query and client graph have the option to display the data on a logarithmic scale in order to catch outliers properly while preserving your perspective of the normal flow of traffic.
On the bottom of the page the top 10 of both passed and blocked queries are shown. This includes the amount a domain has been requested, as well as a percentage of passed or blocked requests respectively. If you have blocklists enabled, you are also able to explicitly block or whitelist a specific domain from this top list with the click of a button. The relevant domains will show up in, under “Whitelist Domains” or “Blocklist Domains”.
The details tab shows a livefeed of completed queries along with reply information. You can refresh the list by clicking the refresh button on the top right of the screen. In it you can find:
Which client queried which domain with its associated DNS record type.
It’s possible that a queried domain with a record type other than a CNAME (e.g. A or AAAA) might show as blocked with a CNAME as the record type in the details table. This is because a response to a query can contain CNAME records which ultimately point to the queried record type within the same answer (try doing a dig on www.azure.com for example). If any of these CNAME records contain domain names that occur within the configured blocklists, the blocklist system will also block this query, but can only do so after Unbound has resolved the relevant domain. The resolve time will therefore be higher on these types of block actions.
The action taken by Unbound, this can either be pass, block or drop. The latter only occurs when a query could not be serviced due to an internal error. “Internal error” can be anything, ranging from a loss of internet connectivity to a crash of Unbound. The common factor is that Unbound marks the return code as SERVFAIL. If the Unbound logs do not show any reason for a drop occuring, the most likely candidate will be a loss of connectivity.
The source of the response. This can be either Recursion, Local, Local-data or cache. ‘Local’ refers to a decision made by Unbound to either block or drop the query. ‘Local-data’ refers to the custom host overrides and its associated aliases or internal local-data entries generated by the system. ‘Cache’ shows responses to clients utilizing the cache.
The return code of the DNS query. Refer to the IANA DNS Parameters for its meaning.
If recursion is involved, how long in milliseconds it took to resolve a domain.
The TTL of the final answer. Answers from recursion will always contain an upstream-defined TTL value, while answers from cache will show a snapshot of the remaining cache TTL value before recursion would have to take place again. Please note that TTL behaviour can be largely dependent on the settings used in.
The blocklist used if a query was blocked.
Either a block or whitelist action button, which can be used in the same way as described above for the “Top domains” in the overview section. Please note that this column will not appear if blocklists are disabled.