No, that's the contrary, they reply too fast, in a sense. If you look at the log I posted, dnsmasq does receive some kind of reply from the unreachable nameservers. I don't know whether this is a crafted reply by the firewall or whether the query actually reached the nameserver but it replied with some kind of failure because the query did not come through the proper route. If you are interested, I can capture a dump of the packets the next time I'm on these networks. Anyway, as I currently understand it, all the nameservers queried by dnsmasq are replying somehow, and dnsmasq only considers the first reply. As a consequence, there is a race between the servers, so DNS resolution will succeed only if the properly routed server replies the fastest.
-- You received this bug notification because you are a member of Desktop Packages, which is subscribed to network-manager in Ubuntu. https://bugs.launchpad.net/bugs/991308 Title: DNS Querying fails if any DNS server is unreachable Status in “dnsmasq” package in Ubuntu: Confirmed Status in “network-manager” package in Ubuntu: Incomplete Bug description: Release: 12.04 Hardware: HP Compaq 6910p Laptop If the backup DNS server is unreachable, dnsmasq does not try to reach primary DNS server. In the following default configuration (clean install of 12.04) 1 out of 4 DNS queries fail. (DNSMasq seems to rotate queries between the listed servers) wlightning@archon:~$ cat /run/nm-dns-dnsmasq.conf server=75.75.75.75 server=75.75.76.76 wlightning@archon:~$ wlightning@archon:~$ 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 127.0.0.1 search hsd1.or.comcast.net wlightning@archon:~$ wlightning@archon:~$ nm-tool NetworkManager Tool State: connected (global) - Device: ttyUSB0 -------------------------------------------------------------- Type: Mobile Broadband (CDMA) Driver: sierra State: disconnected Default: no Capabilities: - Device: wlan0 ---------------------------------------------------------------- Type: 802.11 WiFi Driver: iwl4965 State: unavailable Default: no HW Address: 00:1D:E0:35:69:AF Capabilities: Wireless Properties WEP Encryption: yes WPA Encryption: yes WPA2 Encryption: yes Wireless Access Points - Device: eth0 [Wired connection 1] ------------------------------------------- Type: Wired Driver: e1000e State: connected Default: yes HW Address: 00:1B:38:E7:F5:02 Capabilities: Carrier Detect: yes Speed: 1000 Mb/s Wired Properties Carrier: on IPv4 Settings: Address: 10.0.0.11 Prefix: 24 (255.255.255.0) Gateway: 10.0.0.1 DNS: 75.75.75.75 DNS: 75.75.76.76 wlightning@archon:~$ mtr of 75.75.75.75 (anycast addr): My traceroute [v0.80] archon (0.0.0.0) Sun Apr 29 10:13:58 2012 Keys: Help Display mode Restart statistics Order of fields quit Packets Pings Host Loss% Snt Last Avg Best Wrst StDev 1. 10.0.0.1 0.0% 51 0.6 0.6 0.6 1.5 0.2 2. 73.94.124.1 0.0% 51 9.0 9.2 7.1 14.7 1.5 3. 68.85.148.1 0.0% 51 7.9 10.6 7.4 24.7 4.0 4. 68.87.216.13 0.0% 51 9.2 19.8 8.5 150.8 29.0 5. 68.87.218.162 0.0% 50 10.8 14.1 8.1 85.0 13.4 68.87.218.158 6. 68.87.216.41 0.0% 50 9.5 13.2 9.5 67.4 8.6 7. 75.75.75.75 0.0% 50 9.9 11.0 9.1 17.2 1.8 mtr of 75.75.76.76 (anycast addr): My traceroute [v0.80] archon (0.0.0.0) Sun Apr 29 10:12:42 2012 Keys: Help Display mode Restart statistics Order of fields quit Packets Pings Host Loss% Snt Last Avg Best Wrst StDev 1. 10.0.0.1 0.0% 51 0.6 0.8 0.5 3.6 0.5 2. 73.94.124.1 0.0% 51 9.0 9.3 7.0 18.3 2.5 3. 68.85.148.9 0.0% 51 7.3 9.6 7.2 22.3 2.9 4. 68.85.243.253 0.0% 51 8.3 13.8 7.5 81.9 15.6 5. 68.86.95.97 0.0% 51 14.5 17.2 11.9 33.0 4.4 68.86.91.197 68.86.90.213 68.86.95.93 68.86.95.89 6. 68.86.95.214 0.0% 51 39.5 41.5 38.1 74.5 6.4 7. 68.86.199.130 0.0% 51 51.9 40.8 38.2 55.3 3.3 8. 75.75.76.76 44.0% 50 38.5 40.2 38.3 46.2 2.2 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/dnsmasq/+bug/991308/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
