DNS name resolution does not work after installation

Installing and Using OpenWrt Network and Wireless Configuration
1

Hello
I have installed OpenWRT 21.02 and cannot ping www.google.com from the router. A look at the /etc/resolv.conf file
shows that this is a link to /tmp/resolv.conf. It only says here:

search lan
nameserver 127.0.0.1
nameserver :: 1

I can temporarily save the file with the contents of /tmp/resolv.conf.d/resolv.conf.auto

# Interface office
nameserver 217.237.151.161
nameserver 8.8.8.8
nameserver 8.8.4.4
# Interface wan
nameserver 217.0.43.129
nameserver 217.0.43.145
# Interface wan_6
nameserver 2003: 180: 2: a000: 0: 1: 0: 53
nameserver 2003: 180: 2: b000: 0: 1: 0: 53

fill up, then the name resolution continues until the next reboot of the router.
What can I set on the router so that the correctly configured /tmp/resolv.conf.d/resolv.conf.auto is seen by the router as the default?
The entry /etc/resolv.conf “nameserver 127.0.0.1” says that the router itself acts as a DNS server, but somehow it doesn't work that well.

Best regards
DianiBeach

2

did you set a static IP on the WAN interface ?

If you did, you need to specify the DNSes manually ...

3

in /etc/config/network my wan interface is configured as

config interface 'wan'
        option device 'eth1'
        option proto 'dhcp'
        option peerdns '0'
        list dns '8.8.8.8'
        list dns '8.8.4.4'

It's the last 3 lines that make the difference .... these should then show up in /tmp/resolv.conf.d/resolv.conf.auto

for wan6

config interface 'wan6'
        .......
        option peerdns '0'
        list dns '2001:4860:4860::8888'
        list dns '2001:4860:4860::8844'

Of course, I'm using google DNS - you set your values as you wish

4

Thanks for your feedbacks.
I have done your suggests like

config interface 'wan'                    
        option device 'wan'           
        option type 'bridge'          
        option proto 'pppoe'              
        option username 'xxxxxxxxxxxx'
        option password 'xxxxxxxxx'    
        option ipv6 'auto'                                        
        option peerdns '0'            
        list dns '8.8.8.8'         
        list dns '8.8.4.4'                                        
                                      
config interface 'wan6'      
        option device 'wan'                                       
        option proto 'dhcpv6'         
        option type 'bridge'    
        option peerdns '0'                                        
        list dns '2001:4860:4860::8888'
        list dns '2001:4860:4860::8844'

Now the DNS name resolution runs from the connected clients, but not from the router self.

5

Does this exist on the WAN interface settings page, I only run APs with openwrt, and remove the WAN interfaces :slight_smile:

image

6

Yes

grafik
grafik870×213 7.81 KB

7

What's in /tmp/resolv.conf.d/resolv.conf.auto

8 
/tmp/resolv.conf.d/resolv.conf.auto
# Interface office
nameserver 217.237.151.161
nameserver 8.8.8.8
nameserver 8.8.4.4
# Interface wan
nameserver 8.8.8.8
nameserver 8.8.4.4
# Interface wan_6
9

What's the output of
uci show dhcp.@dnsmasq[]

10

is that relevant, this is a on router issue, not client ?

11 
# uci show dhcp.@dnsmasq[]
dhcp.cfg01411c=dnsmasq
dhcp.cfg01411c.domainneeded='1'
dhcp.cfg01411c.localise_queries='1'
dhcp.cfg01411c.rebind_protection='1'
dhcp.cfg01411c.rebind_localhost='1'
dhcp.cfg01411c.local='/lan/'
dhcp.cfg01411c.domain='lan'
dhcp.cfg01411c.expandhosts='1'
dhcp.cfg01411c.authoritative='1'
dhcp.cfg01411c.readethers='1'
dhcp.cfg01411c.leasefile='/tmp/dhcp.leases'
dhcp.cfg01411c.resolvfile='/tmp/resolv.conf.d/resolv.conf.auto'
dhcp.cfg01411c.localservice='1'
dhcp.cfg01411c.ednspacket_max='1232'
12

Yes, that only affects the router. It is also required for the NTP time server. And for the updates of course.
opkg update
fails in this case.

13

is your /etc/resolv.conf a softlink ?
I still use 19.07, might be different in 21.02.

lrwxrwxrwx 1 root root 16 Jan 19 2021 resolv.conf -> /tmp/resolv.conf

I assume pinging (for instance 8.8.8.8) works, but name resolution fails ?

14

It's the same like 19.07, it's a link
lrwxrwxrwx 1 root root 16 Sep 1 00:20 /etc/resolv.conf -> /tmp/resolv.conf
The pings over IP addresses runs well, only the name resolution fails on the router.

15

Well, that looks fine - if you run

netstat -pant | grep "dnsmasq"

can you see dnsmasq listening to 127.0.0.1 and ::1?

1 Like
16

What does network.wan look like in your device, compared to Setting DNS on my PPPoE WAN - #3 by ajaffarali? ?

17

No, that's not the case.

18

Well, there's your problem - of course, I have no idea why dnsmasq would not be listening on localhost

1 Like
19 
network.loopback=interface
network.loopback.device='lo'
network.loopback.proto='static'
network.loopback.ipaddr='127.0.0.1'
network.loopback.netmask='255.0.0.0'
network.globals=globals
network.globals.ula_prefix='fd49:8bd1:464e::/48'
network.@device[0]=device
network.@device[0].name='br-lan'
network.@device[0].type='bridge'
network.@device[0].ports='lan1' 'lan2' 'lan3' 'lan4'
network.@bridge-vlan[0]=bridge-vlan
network.@bridge-vlan[0].device='br-lan'
network.@bridge-vlan[0].vlan='1'
network.@bridge-vlan[0].ports='lan1' 'lan2'
network.@bridge-vlan[1]=bridge-vlan
network.@bridge-vlan[1].device='br-lan'
network.@bridge-vlan[1].vlan='2'
network.@bridge-vlan[1].ports='lan3' 'lan4'
network.office=interface
network.office.device='br-lan.1'
network.office.proto='static'
network.office.netmask='255.255.255.0'
network.office.ip6assign='60'
network.office.ipaddr='192.168.0.1'
network.office.dns='217.237.151.161' '8.8.8.8' '8.8.4.4'
network.home=interface
network.home.device='br-lan.2'
network.home.proto='static'
network.home.ipaddr='192.168.1.1'
network.home.netmask='255.255.255.0'
network.home.ip6assign='60'
network.@device[1]=device
network.@device[1].name='wan'
network.@device[1].macaddr='c6:41:1e:33:b4:3b'
network.wan=interface
network.wan.device='wan'
network.wan.type='bridge'
network.wan.proto='pppoe'
network.wan.username='xxxxxxxxxxxxx'
network.wan.password='xxxxxxxxx'
network.wan.ipv6='auto'
network.wan.peerdns='0'
network.wan.dns='8.8.8.8' '8.8.4.4' '217.237.151.161'
network.wan6=interface
network.wan6.device='wan'
network.wan6.proto='dhcpv6'
network.wan6.type='bridge'
network.wan6.peerdns='0'
network.wan6.dns='2001:4860:4860::8888' '2001:4860:4860::8844'
dhcp.@dnsmasq[0]=dnsmasq
dhcp.@dnsmasq[0].domainneeded='1'
dhcp.@dnsmasq[0].localise_queries='1'
dhcp.@dnsmasq[0].rebind_protection='1'
dhcp.@dnsmasq[0].rebind_localhost='1'
dhcp.@dnsmasq[0].local='/lan/'
dhcp.@dnsmasq[0].domain='lan'
dhcp.@dnsmasq[0].expandhosts='1'
dhcp.@dnsmasq[0].authoritative='1'
dhcp.@dnsmasq[0].readethers='1'
dhcp.@dnsmasq[0].leasefile='/tmp/dhcp.leases'
dhcp.@dnsmasq[0].resolvfile='/tmp/resolv.conf.d/resolv.conf.auto'
dhcp.@dnsmasq[0].localservice='1'
dhcp.@dnsmasq[0].ednspacket_max='1232'
dhcp.@dnsmasq[0].nonwildcard='0'
dhcp.lan=dhcp
dhcp.lan.interface='lan'
dhcp.lan.start='100'
dhcp.lan.limit='150'
dhcp.lan.leasetime='12h'
dhcp.lan.dhcpv4='server'
dhcp.lan.dhcpv6='server'
dhcp.lan.ra='server'
dhcp.lan.ra_slaac='1'
dhcp.lan.ra_flags='managed-config' 'other-config'
dhcp.wan=dhcp
dhcp.wan.interface='wan'
dhcp.wan.ignore='1'
dhcp.wan.ra_flags='none'
dhcp.odhcpd=odhcpd
dhcp.odhcpd.maindhcp='0'
dhcp.odhcpd.leasefile='/tmp/hosts/odhcpd'
dhcp.odhcpd.leasetrigger='/usr/sbin/odhcpd-update'
dhcp.odhcpd.loglevel='4'
dhcp.office=dhcp
dhcp.office.interface='office'
dhcp.office.start='100'
dhcp.office.limit='150'
dhcp.office.leasetime='12h'
dhcp.office.dhcp_option='192.168.0.1' '217.237.151.161' '8.8.8.8' '8.8.4.4' '1.1.1.1'
dhcp.office.ra='server'
dhcp.office.dhcpv6='server'
dhcp.office.dns='2606:4700:4700::1111' '2001:4860:4860::8888'
dhcp.office.ra_flags='none'
dhcp.home=dhcp
dhcp.home.interface='home'
dhcp.home.start='100'
dhcp.home.limit='150'
dhcp.home.leasetime='12h'
dhcp.home.dhcp_option='192.168.0.1' '217.237.151.161' '8.8.8.8' '8.8.4.4' '1.1.1.1'
dhcp.home.ra='server'
dhcp.home.dhcpv6='server'
dhcp.home.dns='2606:4700:4700::1111' '2001:4860:4860::8888'
dhcp.home.ra_flags='none'
lrwxrwxrwx    1 root     root            16 Sep  1 00:20 /etc/resolv.conf -> /tmp/resolv.conf
-rw-r--r--    1 root     root            47 Oct  6 10:40 /tmp/resolv.conf
-rw-r--r--    1 root     root            48 Oct  6 10:18 /tmp/resolv.conf.ppp

/tmp/resolv.conf.d:
-rw-r--r--    1 root     root           183 Oct  6 10:18 resolv.conf.auto
==> /etc/resolv.conf <==
search lan
nameserver 127.0.0.1
nameserver ::1

==> /tmp/resolv.conf <==
search lan
nameserver 127.0.0.1
nameserver ::1

==> /tmp/resolv.conf.d <==
head: /tmp/resolv.conf.d: I/O error

==> /tmp/resolv.conf.ppp <==
nameserver 217.0.43.129
nameserver 217.0.43.145
21 
# /etc/init.d/dnsmasq restart
udhcpc: started, v1.33.1
udhcpc: sending discover
udhcpc: no lease, failing
udhcpc: started, v1.33.1
udhcpc: sending discover
udhcpc: no lease, failing

and here the syslog

# cat /tmp/log/syslog 
Wed Oct  6 11:41:15 2021 user.notice dnsmasq: DNS rebinding protection is active, will discard upstream RFC1918 responses!
Wed Oct  6 11:41:15 2021 user.notice dnsmasq: Allowing 127.0.0.0/8 responses
Wed Oct  6 12:29:39 2021 daemon.crit dnsmasq[9104]: bad dhcp-option at line 32 of /var/etc/dnsmasq.conf.cfg01411c
Wed Oct  6 12:29:39 2021 daemon.crit dnsmasq[9104]: FAILED to start up
Wed Oct  6 12:29:44 2021 daemon.crit dnsmasq[9163]: bad dhcp-option at line 32 of /var/etc/dnsmasq.conf.cfg01411c
Wed Oct  6 12:29:44 2021 daemon.crit dnsmasq[9163]: FAILED to start up
Wed Oct  6 12:29:49 2021 daemon.crit dnsmasq[9164]: bad dhcp-option at line 32 of /var/etc/dnsmasq.conf.cfg01411c
Wed Oct  6 12:29:49 2021 daemon.crit dnsmasq[9164]: FAILED to start up
Wed Oct  6 12:29:54 2021 daemon.crit dnsmasq[9166]: bad dhcp-option at line 32 of /var/etc/dnsmasq.conf.cfg01411c
Wed Oct  6 12:29:54 2021 daemon.crit dnsmasq[9166]: FAILED to start up
1 Like