So I wanted to have Unbound use IPv6 transport only and not use IPv4 when doing lookups. (This is for fun. I want to see all the dns look ups done in IPv6 for educationsl purpose.)
My computer has IPv6 connectivity (can do curl -6) so I created an Unbound server.
Thought adding do-ip4: no was enough but I'm not getting anything from dig.
My prediction was that my computer is trying to use systemd-resolved instead of unbound but that has nothing to do with IPv6 so I guess not?
Here are my config files and tcpdump
With IPv4 enabled (working)
$ cat /etc/unbound/unbound.conf.d/myunbound.conf
server:
port: 53
verbosity: 0
num-threads: 2
outgoing-range: 512
num-queries-per-thread: 1024
msg-cache-size: 32m
interface: 0.0.0.0
interface: 2001:myipv6addr:20
rrset-cache-size: 64m
cache-max-ttl: 86400
infra-host-ttl: 60
infra-lame-ttl: 120
access-control: 127.0.0.0/8 allow
access-control: 0.0.0.0/0 allow
username: unbound
directory: "/etc/unbound"
use-syslog: no
hide-version: yes
do-ip4: yes
do-ip6: yes
do-udp: yes
do-tcp: yes
# prefer-ip6: no
remote-control:
control-enable: yes
control-port: 953
control-interface: 0.0.0.0
tcpdump -n -vv port 53 -i any for dig o.com
19:56:49.226291 IP6 (flowlabel 0xa269b, hlim 64, next-header UDP (17) payload length: 54) ::1.39522 > ::1.53: [bad udp cksum 0x0049 -> 0xa5ea!] 35213+ [1au] A? o.com. ar: . OPT UDPsize=4096 (46)
19:56:50.222460 IP (tos 0x0, ttl 64, id 49989, offset 0, flags [none], proto UDP (17), length 74)
127.0.0.1.52155 > 127.0.0.1.53: [bad udp cksum 0xfe49 -> 0x7690!] 35213+ [1au] A? o.com. ar: . OPT UDPsize=4096 (46)
19:56:50.222695 IP (tos 0x0, ttl 64, id 47599, offset 0, flags [none], proto UDP (17), length 62)
[myIPv4].41206 > 192.35.51.30.53: [bad udp cksum 0x4644 -> 0x5c52!] 46488% [1au] A? o.com. ar: . OPT UDPsize=4096 DO (34)
19:56:50.292985 IP (tos 0x0, ttl 54, id 26365, offset 0, flags [none], proto UDP (17), length 1153)
192.35.51.30.53 > [myIPv4].41206: [udp sum ok] 46488 NXDomain*- q: A? o.com. 0/8/1 ns: com. SOA a.gtld-servers.net. nstld.verisign-grs.com. 1653044192 1800 900 604800 86400, com. RRSIG, CK0POJMG874LJREF7EFN8430QVIT8BSM.com. Type50, CK0POJMG874LJREF7EFN8430QVIT8BSM.com. RRSIG, TE4S5DTC23DPH5M574GG84GG0Q86T3GM.com. Type50, TE4S5DTC23DPH5M574GG84GG0Q86T3GM.com. RRSIG, 3RL2Q58205687C8I9KC9MV46DGHCNS45.com. Type50, 3RL2Q58205687C8I9KC9MV46DGHCNS45.com. RRSIG ar: . OPT UDPsize=4096 DO (1125)
19:56:50.293239 IP (tos 0x0, ttl 64, id 49997, offset 0, flags [none], proto UDP (17), length 135)
127.0.0.1.53 > 127.0.0.1.52155: [bad udp cksum 0xfe86 -> 0xc2e6!] 35213 NXDomain q: A? o.com. 0/1/1 ns: com. SOA a.gtld-servers.net. nstld.verisign-grs.com. 1653044192 1800 900 604800 86400 ar: . OPT UDPsize=4096 (107)
With IPv4 disabled (not working)
$ cat /etc/unbound/unbound.conf.d/myunbound.conf
server:
port: 53
verbosity: 0
num-threads: 2
outgoing-range: 512
num-queries-per-thread: 1024
msg-cache-size: 32m
interface: 0.0.0.0
interface: 2001:myipv6addr:20
rrset-cache-size: 64m
cache-max-ttl: 86400
infra-host-ttl: 60
infra-lame-ttl: 120
access-control: 127.0.0.0/8 allow
access-control: 0.0.0.0/0 allow
username: unbound
directory: "/etc/unbound"
use-syslog: no
hide-version: yes
do-ip4: no
do-ip6: yes
do-udp: yes
do-tcp: yes
# prefer-ip6: no
remote-control:
control-enable: yes
control-port: 953
control-interface: 0.0.0.0
tcpdump dig k.com
20:02:32.122198 IP6 (flowlabel 0x8897b, hlim 64, next-header UDP (17) payload length: 54) ::1.53805 > ::1.53: [bad udp cksum 0x0049 -> 0x676c!] 15532+ [1au] A? k.com. ar: . OPT UDPsize=4096 (46)
20:02:33.122126 IP (tos 0x0, ttl 64, id 59754, offset 0, flags [none], proto UDP (17), length 74)
127.0.0.1.35568 > 127.0.0.1.53: [bad udp cksum 0xfe49 -> 0xb0a8!] 15532+ [1au] A? k.com. ar: . OPT UDPsize=4096 (46)
20:02:38.126147 IP6 (flowlabel 0x8897b, hlim 64, next-header UDP (17) payload length: 54) ::1.53805 > ::1.53: [bad udp cksum 0x0049 -> 0x676c!] 15532+ [1au] A? k.com. ar: . OPT UDPsize=4096 (46)
20:02:39.122227 IP (tos 0x0, ttl 64, id 59906, offset 0, flags [none], proto UDP (17), length 74)
127.0.0.1.35568 > 127.0.0.1.53: [bad udp cksum 0xfe49 -> 0xb0a8!] 15532+ [1au] A? k.com. ar: . OPT UDPsize=4096 (46)
20:02:44.126099 IP6 (flowlabel 0x8897b, hlim 64, next-header UDP (17) payload length: 54) ::1.53805 > ::1.53: [bad udp cksum 0x0049 -> 0x676c!] 15532+ [1au] A? k.com. ar: . OPT UDPsize=4096 (46)
20:02:45.122363 IP (tos 0x0, ttl 64, id 60247, offset 0, flags [none], proto UDP (17), length 74)
127.0.0.1.35568 > 127.0.0.1.53: [bad udp cksum 0xfe49 -> 0xb0a8!] 15532+ [1au] A? k.com. ar: . OPT UDPsize=4096 (46)
