]> Git — Sourcephile - sourcephile-nix.git/blob - machines/mermet/unbound.nix
public-inbox: change inboxes
[sourcephile-nix.git] / machines / mermet / unbound.nix
1 { pkgs, lib, config, ... }:
2 let
3 inherit (config.services) unbound;
4 inherit (config.users) users;
5 stateDir = "/var/lib/unbound";
6 in
7 {
8 networking.resolvconf.useLocalResolver = true;
9 services.unbound = {
10 enable = true;
11 # DOC: https://calomel.org/unbound_dns.html
12 extraConfig = ''
13 remote-control:
14 control-enable: yes
15 control-interface: /run/unbound/unbound.socket
16
17 server:
18 log-queries: no
19 verbosity: 1
20 interface: 127.0.0.1
21 interface: ::1
22
23 port: 53
24
25 # The file which contains the listing of primary root DNS servers.
26 # To be updated once every six months.
27 root-hints: /var/lib/unbound/named.root
28
29 # Do no answer id.server and hostname.bind queries.
30 hide-identity: yes
31 # Do not answer version.server and version.bind queries.
32 hide-version: yes
33
34 # Will trust glue only if it is within the servers authority.
35 # Harden against out of zone rrsets, to avoid spoofing attempts.
36 # Hardening queries multiple name servers for the same data to make
37 # spoofing significantly harder and does not mandate dnssec.
38 harden-glue: yes
39
40 # Require DNSSEC data for trust-anchored zones, if such data is absent, the
41 # zone becomes bogus. Harden against receiving dnssec-stripped data. If you
42 # turn it off, failing to validate dnskey data for a trustanchor will trigger
43 # insecure mode for that zone (like without a trustanchor). Default on,
44 # which insists on dnssec data for trust-anchored zones.
45 harden-dnssec-stripped: yes
46
47 # Use 0x20-encoded random bits in the query to foil spoof attempts.
48 # http://tools.ietf.org/html/draft-vixie-dnsext-dns0x20-00
49 #
50 # When Unbound sends a query to a remote server it sends the hostname
51 # string in random upper and lower characters. The remote server must
52 # resolve the hostname as if all the characters were lower case. The remote
53 # server must then send the query back to Unbound in the same random upper
54 # and lower characters that Unbound sent. If the characters of the hostname
55 # in the response are in the same format as the query then the dns-0x20
56 # check is satisfied.
57 # Attackers hoping to poison a Unbound DNS cache must therefore guess the
58 # mixed-case encoding of the query and the timing of the return dns answer
59 # in addition to all other fields required in a DNS poisoning attack.
60 # dns-0x20 increases the difficulty of the attack significantly.
61 #
62 # It may result in maybe 0.4% of domains getting no answers
63 # due to no support on the authoritative server side
64 use-caps-for-id: yes
65
66 #cache-min-ttl: 3600
67 cache-max-ttl: 86400
68
69 # Perform prefetching of close to expired message cache entries. If a client
70 # requests the dns lookup and the TTL of the cached hostname is going to
71 # expire in less than 10% of its TTL, unbound will (1st) return the IP of the
72 # host to the client and (2nd) pre-fetch the DNS request from the remote DNS server.
73 # This method has been shown to increase the amount of cached hits by
74 # local clients by 10% on average.
75 prefetch: yes
76
77 # Number of threads to create. 1 disables threading.
78 # This should equal the number of CPU cores in the machine.
79 num-threads: ${toString config.nix.maxJobs}
80
81 # The number of slabs to use for cache and must be a power of 2 times the
82 # number of num-threads set above. more slabs reduce lock contention,
83 # but fragment memory usage.
84 msg-cache-slabs: 8
85 rrset-cache-slabs: 8
86 infra-cache-slabs: 8
87 key-cache-slabs: 8
88
89 # Increase the memory size of the cache. Use roughly twice as much rrset cache
90 # memory as you use msg cache memory. Due to malloc overhead, the total memory
91 # usage is likely to rise to double (or 2.5x) the total cache memory.
92 rrset-cache-size: 32m
93 msg-cache-size: 16m
94
95 # buffer size for UDP port 53 incoming (SO_RCVBUF socket option). This sets
96 # the kernel buffer larger so that no messages are lost in spikes in the traffic.
97 so-rcvbuf: 1m
98
99 # Enforce privacy of these addresses. Strips them away from answers.
100 # It may cause DNSSEC validation to additionally mark it as bogus.
101 # Protects against 'DNS Rebinding' (uses browser as network proxy).
102 # Only 'private-domain' and 'local-data' names are allowed
103 # to have these private addresses. No default.
104 private-address: 192.168.0.0/16
105 private-address: 172.16.0.0/12
106 private-address: 10.0.0.0/8
107
108 # Allow the domain (and its subdomains) to contain private addresses.
109 # local-data statements are allowed to contain private addresses too.
110 #private-domain: "home.lan"
111
112 # If nonzero, unwanted replies are not only reported in statistics, but also
113 # a running total is kept per thread. If it reaches the threshold, a warning
114 # is printed and a defensive action is taken, the cache is cleared to flush
115 # potential poison out of it. A suggested value is 10000000, the default is
116 # 0 (turned off). calomel.org thinks 10K is a good value.
117 unwanted-reply-threshold: 10000
118
119 # IMPORTANT FOR TESTING: If you are testing and setup NSD or BIND on
120 # localhost you will want to allow the resolver to send queries to localhost.
121 # Make sure to set do-not-query-localhost: yes.
122 do-not-query-localhost: yes
123
124 # Should additional section of secure message also be kept clean of unsecure
125 # data. Useful to shield the users of this validator from potential bogus
126 # data in the additional section. All unsigned data in the additional section
127 # is removed from secure messages.
128 val-clean-additional: yes
129 '';
130 };
131 networking.nftables.ruleset = ''
132 add rule inet filter fw2net tcp dport 53 skuid ${users.unbound.name} counter accept comment "Unbound"
133 add rule inet filter fw2net udp dport 53 skuid ${users.unbound.name} counter accept comment "Unbound"
134 '';
135 systemd.services.unbound = {
136 serviceConfig = {
137 RuntimeDirectory = "unbound";
138 RuntimeDirectoryMode = "0700";
139 };
140 preStart = ''
141 install -m 444 -o unbound -g nogroup \
142 ${../../var/named.root} \
143 /var/lib/unbound/named.root
144 '';
145 };
146 }