On my home network, I'm using a (Raspbian) Raspberry Pi as a wifi router with hostapd
, isc-dhcp-server
, radvd
, pihole
, and dnscrypt-proxy
installed. I do not use dhcpcd
, I use dhclient
. As I only get one ipv4 address and one ipv6 address from my ISP, I have both dhcp and dhcpv6 servers and NAT set up. When connecting to the wifi network, everything works perfectly and I can use both ipv4 and ipv6 to connect to the internet. However, if I ping
a host, the ipv4 address is used:
$ ping google.com
PING google.com (216.58.212.174) 56(84) bytes of data.
64 bytes from ams15s22-in-f174.1e100.net (216.58.212.174): icmp_seq=1 ttl=55 time=16.1 ms
64 bytes from ams15s22-in-f174.1e100.net (216.58.212.174): icmp_seq=2 ttl=55 time=16.3 ms
64 bytes from ams15s22-in-f174.1e100.net (216.58.212.174): icmp_seq=3 ttl=55 time=16.5 ms
I want to use ipv6 by default. Without the Raspberry Pi, ping
uses the ipv6 address:
$ ping google.com
PING google.com(ams15s22-in-x0e.1e100.net (2a00:1450:400e:801::200e)) 56 data bytes
64 bytes from ams15s22-in-x0e.1e100.net (2a00:1450:400e:801::200e): icmp_seq=1 ttl=56 time=103 ms
64 bytes from ams15s22-in-x0e.1e100.net (2a00:1450:400e:801::200e): icmp_seq=2 ttl=56 time=18.5 ms
64 bytes from ams15s22-in-x0e.1e100.net (2a00:1450:400e:801::200e): icmp_seq=3 ttl=56 time=16.8 ms
This behaviour extends to browsers, curl
, wget
...
I've tested the network both with and without the Pihole DNS server, there's no difference in behaviour, so I don't think that would be the cause.
My local setup:
$ ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: enp2s0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc fq_codel state DOWN group default qlen 1000
link/ether 30:65:ec:b8:45:66 brd ff:ff:ff:ff:ff:ff
3: wlp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether b2:a5:95:7c:58:a0 brd ff:ff:ff:ff:ff:ff
inet 192.168.0.161/24 brd 192.168.0.255 scope global dynamic noprefixroute wlp3s0
valid_lft 83213sec preferred_lft 83213sec
inet6 fd97:367f:e5b4:8c28:17e3:4ca9:b7b8:3150/64 scope global dynamic noprefixroute
valid_lft 86275sec preferred_lft 14275sec
inet6 fe80::755f:ab92:41fe:9872/64 scope link noprefixroute
valid_lft forever preferred_lft forever
/etc/gai.conf
is empty.
My Raspberry Pi setup:
/etc/dhcp/dhcpd.conf
:
default-lease-time 86400;
authoritative;
subnet 192.168.0.0 netmask 255.255.255.0 {
range 192.168.0.2 192.168.0.254;
option routers 192.168.0.1;
option domain-name-servers 192.168.0.1;
}
/etc/dhcp/dhcpd6.conf
:
default-lease-time 2592000;
authoritative;
subnet6 fd97:367f:e5b4:8c28::/64 {
range6 fd97:367f:e5b4:8c28:0000:0000:0000:2 fd97:367f:e5b4:8c28:ffff:ffff:ffff:fffe;
option dhcp6.name-servers fd97:367f:e5b4:8c28:0000:0000:0000:1;
}
/etc/network/interfaces
:
auto lo
iface lo inet loopback
auto eth0
allow-hotplug eth0
iface eth0 inet dhcp
iface eth0 inet6 auto
privext 2
auto wlan0
allow-hotplug wlan0
iface wlan0 inet static
address 192.168.0.1
netmask 255.255.255.0
up iptables-restore < /etc/iptables.ipv4.nat
iface wlan0 inet6 static
address fd97:367f:e5b4:8c28:0000:0000:0000:1
netmask 64
dad-attempts 0
up ip6tables-restore < /etc/iptables.ipv6.nat
/etc/radvd.conf
:
interface wlan0 {
AdvSendAdvert on;
prefix fd97:367f:e5b4:8c28::/64 {};
};
/etc/iptables.ipv4.nat
:
# Generated by iptables-save v1.6.0 on Fri Feb 8 13:46:33 2019
*filter
:INPUT ACCEPT [74:5800]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [96:7812]
-A FORWARD -i eth0 -o wlan0 -m state --state RELATED,ESTABLISHED -j ACCEPT
-A FORWARD -i wlan0 -o eth0 -j ACCEPT
COMMIT
# Completed on Fri Feb 8 13:46:33 2019
# Generated by iptables-save v1.6.0 on Fri Feb 8 13:46:33 2019
*nat
:PREROUTING ACCEPT [1844:56256]
:INPUT ACCEPT [4:513]
:OUTPUT ACCEPT [6:492]
:POSTROUTING ACCEPT [1:48]
-A POSTROUTING -o eth0 -j MASQUERADE
COMMIT
# Completed on Fri Feb 8 13:46:33 2019
/etc/iptables.ipv6.nat
:
# Generated by ip6tables-save v1.6.0 on Fri Feb 8 13:59:43 2019
*filter
:INPUT ACCEPT [105:9056]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [63:7044]
-A FORWARD -i eth0 -o wlan0 -m state --state RELATED,ESTABLISHED -j ACCEPT
-A FORWARD -i wlan0 -o eth0 -j ACCEPT
COMMIT
# Completed on Fri Feb 8 13:59:43 2019
# Generated by ip6tables-save v1.6.0 on Fri Feb 8 13:59:43 2019
*nat
:PREROUTING ACCEPT [7:584]
:INPUT ACCEPT [1:104]
:OUTPUT ACCEPT [1:140]
:POSTROUTING ACCEPT [1:140]
-A POSTROUTING -o eth0 -j MASQUERADE
COMMIT
# Completed on Fri Feb 8 13:59:43 2019
net.ipv4.ip_forward
and net.ipv6.conf.all.forwarding
are set to 1 in /etc/sysctl.conf
. dhcpcd
is disabled and stopped.
eth0
. (See/etc/network/interfaces
) NAT is used betweeneth0
andwlan0
both on ipv4 and ipv6 level. I'm sorry if this wasn't clear./etc/network/interfaces
? It contains thelo
,eth0
, andwlan0
interfaces?ip a
!