Suspicious DNS Entries

maxxxx.power

Been referenced here: netgate forum, as well as Reddit.

Numerous DNS request on Port 53 to 176.119.4.8 or .9 despite no machines using this IP, including Windows Server Root Hints.

Today I am seeing a large amount of permission denied entries in the Resolver log. Turned on Level 3 logging as per the other post:

Here is what I am seeing:

Jan 14 10:57:28 	unbound 	91347:0 	debug: cache memory msg=366627 rrset=1047863 infra=324916 val=0
Jan 14 10:57:28 	unbound 	91347:0 	debug: return error response SERVFAIL
Jan 14 10:57:28 	unbound 	91347:0 	debug: out of query targets -- returning SERVFAIL
Jan 14 10:57:28 	unbound 	91347:0 	info: processQueryTargets: 73.4.119.176.in-addr.arpa. PTR IN
Jan 14 10:57:28 	unbound 	91347:0 	info: error sending query to auth server 176.119.4.8 port 53
Jan 14 10:57:28 	unbound 	91347:0 	notice: remote address is 176.119.4.8 port 53
Jan 14 10:57:28 	unbound 	91347:0 	notice: sendto failed: Permission denied
Jan 14 10:57:28 	unbound 	91347:0 	debug: sending to target: <4.119.176.in-addr.arpa.> 176.119.4.8#53
Jan 14 10:57:28 	unbound 	91347:0 	info: sending query: 73.4.119.176.in-addr.arpa. PTR IN
Jan 14 10:57:28 	unbound 	91347:0 	info: processQueryTargets: 73.4.119.176.in-addr.arpa. PTR IN
Jan 14 10:57:28 	unbound 	91347:0 	info: error sending query to auth server 176.119.4.9 port 53
Jan 14 10:57:28 	unbound 	91347:0 	notice: remote address is 176.119.4.9 port 53
Jan 14 10:57:28 	unbound 	91347:0 	notice: sendto failed: Permission denied
Jan 14 10:57:28 	unbound 	91347:0 	debug: sending to target: <4.119.176.in-addr.arpa.> 176.119.4.9#53
Jan 14 10:57:28 	unbound 	91347:0 	info: sending query: 73.4.119.176.in-addr.arpa. PTR IN
Jan 14 10:57:28 	unbound 	91347:0 	info: processQueryTargets: 73.4.119.176.in-addr.arpa. PTR IN
Jan 14 10:57:28 	unbound 	91347:0 	info: query response was REFERRAL
Jan 14 10:57:28 	unbound 	91347:0 	info: reply from <176.in-addr.arpa.> 204.61.216.100#53
Jan 14 10:57:28 	unbound 	91347:0 	info: response for 73.4.119.176.in-addr.arpa. PTR IN
Jan 14 10:57:28 	unbound 	91347:0 	info: iterator operate: query 73.4.119.176.in-addr.arpa. PTR IN
Jan 14 10:57:28 	unbound 	91347:0 	debug: iterator[module 0] operate: extstate:module_wait_reply event:module_event_reply
Jan 14 10:57:28 	unbound 	91347:0 	debug: cache memory msg=366432 rrset=1047613 infra=324916 val=0

Any info?

maxxxx.power

To clarify a bit, the permission denied is likely because that host is blocked by both pfBlocker as a Blacklisted IP, and also I have a FW rule blocking that entire subnet. I'd like to know WHERE these requests are coming from - all my local devices use PF itself as the DNS server.

The only IPs listed in DNS under General, are 127.0.01, my two DCs, and CloudFlare.

johnpoz

@maxxxx-power said in Suspicious DNS Entries:

all my local devices use PF itself as the DNS server.

Then log your queries on unbound to see where what is being asked for when it unbound looks to talk to those.. Ie bump your log verb up. Prob level 5 should show help for sure.

Why would you have cloudflare or other servers listed for NS if your using unbound as resolver?

maxxxx.power

Thanks John - I upped verbosity to 5.

Using DNS Resolver, and I do not have forwarding enabled. I thought those entries needed to be populated for PF itself to lookup entries when it didn't have an answer. I guess those entries don't matter at all since I am resolving, not forwarding?

johnpoz

yeah if your resolving the only thing that should be there is localhost

Pfsense will ask itself, and then either resolve or will go ask your local AD for that domain that you setup in the domain overrrides.

If level 5 does not give you queries in the log, then you can turn it on on the custom box.

maxxxx.power

Okay, got all that mess cleaned up. I haven't seen that IP come up in the logs recently. I've got it logging to librenms and will search again later.

Thanks again John.

maxxxx.power

Still nothing for the "suspicious" IP. And to be honest John, I think you've fixed a host of other problems. Hosts losing DNS resolution for internal names at times, ad blocking intermittent, all gone. I can't thank you enough. I really thought I still needed additional servers in the General Setup fields.