connman and nsswitch not working properly

motorious · March 30, 2019 at 7:21 PM

LibreELEC 9.0.1 on RaspPi 3+

(didn't work on 8.2.5 either so I upgraded to 9.0.1)

updated hosts file via '/storage/.config/hosts.conf' rebooted

name resolves using DNS provided by DHCP server. It "should" look at the hosts file first per the nsswitch.conf file:

However, when I try to ping it, I get the DNS IP returned instead of what I set manually...

Quote

# cat /etc/nsswitch.conf
# /etc/nsswitch.conf
#
# Example configuration of GNU Name Service Switch functionality.
#

passwd: files
group: files
shadow: files
gshadow: files

hosts: files mdns_minimal [NOTFOUND=return] dns <<<---------HERE
networks: files dns

protocols: files
services: files
ethers: files
rpc: files

netgroup: files

# cat /etc/hosts
# hosts.conf

# This configuration file allows you to manually map hostnames to
# IP addresses

# Format: <ipaddress> <hostname1> <hostname2>
# Example: 192.168.0.3 libreelec libreelec.mynetwork

# NOTE: do not edit /etc/hosts directly
# edit /storage/.config/hosts.conf then reboot
<host1> <IP2>
<host2> <IP2>
<host3> <IP2>
127.0.0.1 localhost <hostname>
::1 localhost ip6-localhost ip6-loopback <hostname>

# ping <host1>
PING <host1> (<IP1>): 56 data bytes
64 bytes from <IP1>: seq=0 ttl=246 time=36.021 ms <<<-------expected outcome is <IP2> from hosts file.

# nslookup <host1>
Server: <DNS#1 IP> <<<--------This should be 'localhost' I believe...
Address 1: <DNS#1 IP> <DNS#1 HOSTNAME>
Name: <host1>
Address 1: <IP1> server-<IP1>.<domain>

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Obviously names and IP's have been redacted to protect the innocent.

I would like to add 127.0.0.1 as a nameserver in my resolv.conf file but it gets overwritten every time I reboot. I'd also like to keep the other three nameservers it gets from DHCP as well.

Any help on what else I can try or look at to get this thing to resolve the name from the hosts file properly?

Tried removing the 'r' from connman.service that I saw in another thread for caching DNS but that didn't work for my case.

TIA!

**chewitt** · March 31, 2019 at 7:05 AM Official Post

Connman gained the ability to ignore ntp from gateways (e.g. the dns/dhcp service in domestic routers) in these commits which LE includes

connman/connman.git - Connection Manager

but I recently noticed a typo which means it cannot work:

connman/connman.git - Connection Manager

Connman was version bumped to include this and other fixes in our master and 9.0 branches in the last couple of days, so assuming this is related to the issue, it should be resolved [sic] in the next LE update.

motorious · March 31, 2019 at 12:16 PM

sorry for my ignorance but I don't see the correlation between connman and the JEOS failing to use the hosts file first for name resolution instead of DNS....

**vpeter** · March 31, 2019 at 4:14 PM

Just add nameserver 127.0.0.1 to LibreELEC settings?

Also using file /storage/.config/hosts.conf works to for name resolution.

motorious · April 3, 2019 at 7:58 PM

Thanks vpeter, I have already tried both suggestions with no luck. hosts.conf updates the hosts file correctly after reboot but a nslookup <host> shows it's using DNS for resolution instead of local hosts file. To add nameserver to LibreELEC settings I had to use static instead of DHCP but even though it still bypassed the local hosts file even when I did that. So frustrating...can't figure it out. It "should" work but just doesn't for some bizarre reason.

Seems no matter what I do it bypasses the hosts file and only uses DNS for name resolution. I have an addon that requires specific name to IP resolution and the DNS my gateway uses (VPN) is not something I have any access to.

**mglae** · April 3, 2019 at 11:09 PM

nslookup = name server lookup- the tool is only querying DNS servers.

Use getent hosts <name> to query NSS.

motorious · April 4, 2019 at 1:38 AM

thanks for the tip mglae, I wasn't familiar with that command. I ran it and get the same results though unfortunately...

# getent hosts <host1>
<IP1> host1.subdomain.domain.com host1.com host1.domain.com

The addon I use doesn't use that command (I believe) to resolve the name so even if it did work I don't think it would solve my problem with the addon reaching a specific IP based on the hostname...

Going to backup all of my settings and so forth and try rebuilding from scratch...

motorious · April 4, 2019 at 1:43 AM

OMG..I'm so freaking embarrassed... I transposed the hosts file and put the host name before the IP....

I apologize to everyone for my ignorance, once I put the IP first in the hosts.conf file everything worked.

Might take me awhile to pull my foot out of mouth.