Re: [Dorset] New DNS Server Problem
On Thursday, 31 March 2022 13:05:00 BST Terry Coles wrote: > For a system that used to work, the Webserver at WMT is throwing up numerous > problems. After fixing the erroneous conflict yesterday, I now find that > devices are not being given a default route. I've resolved this. Having spent quite some time trying to get my head round the man page for dnsmasq, I came to the conclusion that the local lookups were being rejected because the device names in my hosts.dnsmasq file had no dots in them. I've experimented with adding various suffixes and ended up with a simple '.l' on the end of each device and it works. (A dot on it's own didn't work, even though my reading of the man page led me to believe that it should. I also thought about using '.lc', bit that is a real domain suffix (Saint Lucia) and also 'local', but that is apparently reserved for IETF use, so I decided to stick with '.l', since it doesn't conflict with any real ones and it's shorter to type.) I know my problem was a bit of a corner case, but I'm really pleased to finally understand it -- Terry Coles -- Next meeting: Online, Jitsi, Tuesday, 2022-05-04 20:00 Check to whom you are replying Meetings, mailing list, IRC, ... http://dorset.lug.org.uk New thread, don't hijack: mailto:dorset@mailman.lug.org.uk
Re: [Dorset] New DNS Server Problem
On Thursday, 31 March 2022 15:36:44 BST Terry Coles wrote: > I've just remembered that I have the ability to connect with another Kubuntu > machine (this desktop) by plugging in a USB WiFi Adaptor, that I'd > forgotten that I have. I did. It worked. So the problem seems to be in my > laptop. :oops Hi, I've found out a couple of things since yesterday. First; ip a doesn't identify the DNS Server in use and nor does ip route, which only provides the default route. However, nmcli does. On my desktop which is connected to the Internet via Ethernet to my home router and to the test network via WiFi, I get: nmcli dev show | grep DNS IP4.DNS[1]: 192.168.1.1 IP4.DNS[1]: 192.168.0.1 Which shows that the machine has knowledge of a DNS Server via my home router and the DNS Server on the test network (the Webserver). I would expect therefore that nslookup should work from my desktop to identify items on the test network. The trouble is that this only half works. From my desktop: terry@OptiPlex:~$ nslookup wmt-guest.com Server: 127.0.0.53 Address:127.0.0.53#53 Non-authoritative answer: Name: wmt-guest.com Address: 192.168.0.1 Name: wmt-guest.com Address: 127.0.0.1 Good. But if I try to resolve the identity of one of the other devices on the real network (held in a separate file and identified in dnsmasq.conf by the line 'addn-hosts=/etc/ hosts.dnsmasq'), it doesn't work: terry@OptiPlex:~$ nslookup sumppi Server: 127.0.0.53 Address:127.0.0.53#53 ** server can't find sumppi: SERVFAIL Unless I include the identity of the server. terry@OptiPlex:~$ nslookup sumppi 192.168.0.1 Server: 192.168.0.1 Address:192.168.0.1#53 Name: sumppi Address: 192.168.0.2 I can resolve sumppi when logged into the Webserver via ssh. So why does nslookup fail when I try to use it from a device logged into the test network unless I include the identity of the DNS Server? -- Terry Coles -- Next meeting: Online, Jitsi, Tuesday, 2022-05-04 20:00 Check to whom you are replying Meetings, mailing list, IRC, ... http://dorset.lug.org.uk New thread, don't hijack: mailto:dorset@mailman.lug.org.uk
Re: [Dorset] New DNS Server Problem
On Thursday, 31 March 2022 15:29:29 BST Terry Coles wrote: > Returning to the point. All devices that I have here work properly apart > from the laptop which apparently doesn't get given an IP Address (except > that it does). If connecting with the laptop doesn't trigger activity in > syslog similar to that above, the presumably the DNS Server address is > never sent out. I've just remembered that I have the ability to connect with another Kubuntu machine (this desktop) by plugging in a USB WiFi Adaptor, that I'd forgotten that I have. I did. It worked. So the problem seems to be in my laptop. :oops -- Terry Coles -- Next meeting: Online, Jitsi, Tuesday, 2022-05-04 20:00 Check to whom you are replying Meetings, mailing list, IRC, ... http://dorset.lug.org.uk New thread, don't hijack: mailto:dorset@mailman.lug.org.uk
Re: [Dorset] New DNS Server Problem
On Thursday, 31 March 2022 13:05:00 BST Terry Coles wrote: > So the problem seems to be that connecting devices don't get the identity of > the DNS Server along with their IP Address. A thought. While I was struggling yesterday with the apparent IP Address conflict, (which was buried using noarp), I found that my laptop didn't trigger any activity in syslog, but other devices did. By tailing syslog while connecting with my phone, I got the following (log-queries enabled in dnsmasq.conf): Mar 31 14:10:00 WMT-Webserver dnsmasq-dhcp[539]: 993883321 available DHCP range: 192.168.0.100 -- 192.168.0.250 Mar 31 14:10:00 WMT-Webserver dnsmasq-dhcp[539]: 993883321 vendor class: android- dhcp-11 Mar 31 14:10:00 WMT-Webserver dnsmasq-dhcp[539]: 993883321 client provides name: OnePlus-Nord2-5G Mar 31 14:10:00 WMT-Webserver dnsmasq-dhcp[539]: 993883321 DHCPREQUEST(eth0) 192.168.0.212 6e:ab:63:d7:20:a6 Mar 31 14:10:00 WMT-Webserver dnsmasq-dhcp[539]: 993883321 tags: eth0 Mar 31 14:10:00 WMT-Webserver dnsmasq-dhcp[539]: 993883321 DHCPACK(eth0) 192.168.0.212 6e:ab:63:d7:20:a6 OnePlus-Nord2-5G Mar 31 14:10:00 WMT-Webserver dnsmasq-dhcp[539]: 993883321 requested options: 1:netmask, 3:router, 6:dns-server, 15:domain-name, Mar 31 14:10:00 WMT-Webserver dnsmasq-dhcp[539]: 993883321 requested options: 26:mtu, 28:broadcast, 51:lease-time, 58:T1, Mar 31 14:10:00 WMT-Webserver dnsmasq-dhcp[539]: 993883321 requested options: 59:T2, 43:vendor-encap, 114, 108 Mar 31 14:10:00 WMT-Webserver dnsmasq-dhcp[539]: 993883321 next server: 192.168.0.1 Mar 31 14:10:00 WMT-Webserver dnsmasq-dhcp[539]: 993883321 sent size: 1 option: 53 message-type 5 Mar 31 14:10:00 WMT-Webserver dnsmasq-dhcp[539]: 993883321 sent size: 4 option: 54 server-identifier 192.168.0.1 Mar 31 14:10:00 WMT-Webserver dnsmasq-dhcp[539]: 993883321 sent size: 4 option: 51 lease-time 12h Mar 31 14:10:00 WMT-Webserver dnsmasq-dhcp[539]: 993883321 sent size: 4 option: 58 T1 6h Mar 31 14:10:00 WMT-Webserver dnsmasq-dhcp[539]: 993883321 sent size: 4 option: 59 T2 10h30m Mar 31 14:10:00 WMT-Webserver dnsmasq-dhcp[539]: 993883321 sent size: 4 option: 1 netmask 255.255.255.0 Mar 31 14:10:00 WMT-Webserver dnsmasq-dhcp[539]: 993883321 sent size: 4 option: 28 broadcast 192.168.0.255 Mar 31 14:10:00 WMT-Webserver dnsmasq-dhcp[539]: 993883321 sent size: 4 option: 6 dns-server 192.168.0.1 Mar 31 14:10:00 WMT-Webserver dnsmasq-dhcp[539]: 993883321 sent size: 4 option: 3 router 192.168.0.1 Note that the identity of the DNS Server is sent, although I can't see it on the phone with ip a. Does ip a provide the identity of the DNS Server on Android? Returning to the point. All devices that I have here work properly apart from the laptop which apparently doesn't get given an IP Address (except that it does). If connecting with the laptop doesn't trigger activity in syslog similar to that above, the presumably the DNS Server address is never sent out. I don't know if this gives any further clues as to what is going on here. -- Terry Coles -- Next meeting: Online, Jitsi, Tuesday, 2022-05-04 20:00 Check to whom you are replying Meetings, mailing list, IRC, ... http://dorset.lug.org.uk New thread, don't hijack: mailto:dorset@mailman.lug.org.uk
[Dorset] New DNS Server Problem
For a system that used to work, the Webserver at WMT is throwing up numerous problems. After fixing the erroneous conflict yesterday, I now find that devices are not being given a default route. This hardware works fine when a phone or an iPad is connected, but not with my Kubuntu Laptop. Here is the contents of dnsmasq.conf: interface=eth0 # Settings for interface eth0 listen-address=192.168.0.1 # Specify the address to listen on server=192.168.0.1 # This is the only DNS Server domain-needed# Don't forward short names bogus-priv # Drop the non-routed address spaces. dhcp-range=eth0,192.168.0.100,192.168.0.250,12h # Set IP range and lease time dhcp-option=3,192.168.0.1 dhcp-option=6,192.168.0.1 # List of domains to respond to address=/wmt-guest.com/192.168.0.1 addn-hosts=/etc/hosts.dnsmasq # Increase logging level #log-dhcp #log-queries I think that the mobile devices work because they are successfully intercepted by nodogsplash, the Captive Portal code which redirects them to the content. This doesn't happen with the laptop, but if I issue ip route on any device, the DNS Server doesn't show up. I know the server is working because if I do a lookup with the identity of the server included it works: terry@XPS-13:~$ nslookup sumppi 192.168.0.1 Server: 192.168.0.1 Address:192.168.0.1#53 Name: sumppi Address: 192.168.0.2 So the problem seems to be that connecting devices don't get the identity of the DNS Server along with their IP Address. The nodogsplash code on this server hasn't been updated for around a year, but I wouldn't necessarily have noticed at the time if there was a problem with the default route because the vast majority of our Visitors don't lug laptops onto the site. I occasionally use a laptop on site, but only to ssh into devices and that works of course. Anything else that I should check? -- Terry Coles -- Next meeting: Online, Jitsi, Tuesday, 2022-05-04 20:00 Check to whom you are replying Meetings, mailing list, IRC, ... http://dorset.lug.org.uk New thread, don't hijack: mailto:dorset@mailman.lug.org.uk
