Running Kubuntu 16.04
Sometimes the name resolution gets slow. In previous Ubuntu versions, the problem was usually in resolv.conf and was easy to fix. In 16.04 all the DNS resolution is hidden in a NetworkManager+resolvconf+dsnmasq maze, and I don't know how I can figure out the actual DNS (dig says it's 127.0.1.1).
Could a kind soul explain:
- how NetworkManager, resolvconf, and dsnmasq work together (because this is something that is not explained in the documentation of each)
- how can I debug DNS performance problems
Additional information
ls -al /etc/resolv.conf
lrwxrwxrwx 1 root root 29 Apr 8 2017 /etc/resolv.conf -> ../run/resolvconf/resolv.conf
cat /etc/resolv.conf
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
# DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 127.0.1.1
dpkg -l *dnsmasq*
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-==============-============-============-=================================
un dnsmasq <none> <none> (no description available)
ii dnsmasq-base 2.75-1ubuntu amd64 Small caching DNS proxy and DHCP/
host -v www.ebay.com
Trying "www.ebay.com"
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 46563
;; flags: qr rd ra; QUERY: 1, ANSWER: 3, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;www.ebay.com. IN A
;; ANSWER SECTION:
www.ebay.com. 292 IN CNAME slot9428.ebay.com.edgekey.net.
slot9428.ebay.com.edgekey.net. 10094 IN CNAME e9428.b.akamaiedge.net.
e9428.b.akamaiedge.net. 12 IN A 104.80.20.236
Received 122 bytes from 127.0.1.1#53 in 2 ms
Trying "e9428.b.akamaiedge.net"
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 35831
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
;; QUESTION SECTION:
;e9428.b.akamaiedge.net. IN AAAA
;; AUTHORITY SECTION:
b.akamaiedge.net. 674 IN SOA n0b.akamaiedge.net. hostmaster.akamai.com. 1564414527 1000 1000 1000 1800
Received 101 bytes from 127.0.1.1#53 in 2 ms
Trying "e9428.b.akamaiedge.net"
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 16147
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
;; QUESTION SECTION:
;e9428.b.akamaiedge.net. IN MX
;; AUTHORITY SECTION:
b.akamaiedge.net. 992 IN SOA n0b.akamaiedge.net. hostmaster.akamai.com. 1564414845 1000 1000 1000 1800
Received 101 bytes from 127.0.1.1#53 in 2 ms
cat /etc/network/interfaces
# interfaces(5) file used by ifup(8) and ifdown(8)
auto lo
iface lo inet loopback
cat /etc/hosts | head
127.0.0.1 localhost
127.0.1.1 Xenoid
# The following lines are desirable for IPv6 capable hosts
::1 localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts
cat /etc/NetworkManager/NetworkManager.conf
[main]
plugins=ifupdown,keyfile,ofono
dns=dnsmasq
[ifupdown]
managed=false
cat /etc/nsswitch.conf
# /etc/nsswitch.conf
#
# Example configuration of GNU Name Service Switch functionality.
# If you have the `glibc-doc-reference' and `info' packages installed, try:
# `info libc "Name Service Switch"' for information about this file.
passwd: compat
group: compat
shadow: compat
gshadow: files
hosts: files mdns4_minimal [NOTFOUND=return] dns
networks: files
protocols: db files
services: db files
ethers: db files
rpc: db files
netgroup: nis
0 Answers