Weird DNS issue with Android Wifi Calling
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Hi,
I've just done this, and I think I've found the culprit.
For some reason my DNS isn't responding to this DNS query, you can see it trying my backup DNS, whereas Google responds first time. Anyone have any idea why?! All other DNS queries look fine.
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$ dig epdg.epc.mnc030.mcc234.pub.3gppnetwork.org a
; <<>> DiG 9.8.3-P1 <<>> epdg.epc.mnc030.mcc234.pub.3gppnetwork.org a
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 64656
;; flags: qr rd ra; QUERY: 1, ANSWER: 3, AUTHORITY: 6, ADDITIONAL: 0;; QUESTION SECTION:
;epdg.epc.mnc030.mcc234.pub.3gppnetwork.org. IN A;; ANSWER SECTION:
epdg.epc.mnc030.mcc234.pub.3gppnetwork.org. 300 IN A 109.249.188.56
epdg.epc.mnc030.mcc234.pub.3gppnetwork.org. 300 IN A 109.249.180.0
epdg.epc.mnc030.mcc234.pub.3gppnetwork.org. 300 IN A 109.249.186.72;; AUTHORITY SECTION:
mnc030.mcc234.pub.3gppnetwork.org. 86400 IN NS j4.nstld.com.
mnc030.mcc234.pub.3gppnetwork.org. 86400 IN NS k4.nstld.com.
mnc030.mcc234.pub.3gppnetwork.org. 86400 IN NS g4.nstld.com.
mnc030.mcc234.pub.3gppnetwork.org. 86400 IN NS l4.nstld.com.
mnc030.mcc234.pub.3gppnetwork.org. 86400 IN NS f4.nstld.com.
mnc030.mcc234.pub.3gppnetwork.org. 86400 IN NS a4.nstld.com.;; Query time: 282 msec
;; SERVER: 192.168.223.1#53(192.168.223.1)
;; WHEN: Mon Mar 28 17:29:26 2016
;; MSG SIZE rcvd: 219Resolves here.
What do you get? You'll want to be sure you're pointing drill at the resolver these clients are using if doing it from pfSense.
eg. $ drill @127.0.0.1 epdg.epc.mnc030.mcc234.pub.3gppnetwork.org a
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Thats the weird thing. If I do a NSLOOKUP on one of my machines it resolves fine - it's simply the request from the android device that isn't being responded to. I setup a log on my DNS Server to show it's received and sent packets, and the DNS service doesn't seem to be getting these DNS queries. I don't understand, there's no firewall on the DNS server :/
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I found a tool that did a NSLOOKUP style thing on Android, and that got a response from my DNS server so I analysed the differences in packets. I've found it.
The MAC address seems to be wrong on the DNS request.
The ones that work have this:
Dst: Universa_08:67:34 (WINDOWS MAC ADDRESS)
The ones that get no response have this:
Dst: Microsof_01:f4:01 (00:15:5d:01:f4:01) - which appears to be Google DNS's mac address.
Why is the MAC address wrong?!
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Sorry to post (again), but I changed my DNS to OpenDNS to test, and it still sends it the wrong MAC address, but it responds anyway. Seems to be an android bug, any way to setup my windows server to ignore checking the MAC address and accept the packet?
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MAC addresses are only locally relevant, only visible on the same broadcast domain. That's not Google DNS's MAC, it's your default gateway's MAC. Sounds like you have an IP conflict for your gateway IP. Only one MAC should ever answer for a given IP.
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@cmb:
MAC addresses are only locally relevant, only visible on the same broadcast domain. That's not Google DNS's MAC, it's your default gateway's MAC. Sounds like you have an IP conflict for your gateway IP. Only one MAC should ever answer for a given IP.
Thanks for the response, thanks for the correction on MAC addresses. I'm not saying you're incorrect, but I'm just confused as to why only my android device (and only on that one DNS request) is using my gateway (pfsense) mac while talking to my internal DNS server. Im 99% positive my pfsense server and DNS server are the only computers using their ip addresses. I suppose the easy way to fix this (can't test currently as now in bed) is to set google DNS as my secondary DNS, as I see it always checks that after not getting a response from the primary, but it'd be nice to fix the problem properly.
What do you think I should try
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Look at android. What are its exact, configured name servers when connected to this network? The different MAC addresses could also also be queries to two different local hosts.
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"I'm not saying you're incorrect"
Your kind of trying to hint at it ;) Sorry to inform you but Derelict is correct here.. (as always) MAC are local, so unless your in the DC where one of googles namerservers are connected to the same L2 you are that is not googles mac address ;)
I never get why anyone would set a 2nd name server that do not have the same data.. That fine if you want to point to say google and opendns out on the public internet. But if you want too resolve your local stuff you have to point at a name server that resolves your local stuff. So it is pointless to point at pfsense, and then 2nd point to google..
If you need failover then you should be pointing to 2 local nameservers that both resolve your local stuff, and then either forward and resolve stuff that is not local. I would concur with Derelict as well to the assumption that you have a duplicate IP issue. You should never get 2 different mac back for the same IP.. So clearly you got something wrong on your network..
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It's right up there in the windns.PNG file. First it asks 10.0.1.30 then 10.0.1.22. Neither of which return answers. Look at your arp table and see if the two MACs match those two IP addresses. The question is why those do not return answers.
A better question is what local DNS servers did the person who designed this network intend to be used by local hosts?
Read the post above again. All configured name servers need to return the same answers to the same queries. At least for local records. For internet results it's possible they could get and cache different answers.
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I assumed you were using Google's DNS given the comment re: the MAC. Source of the problem still sounds the same, just on a diff IP. If the DNS server in question is a local IP, then it's that local IP that has the IP conflict.
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I feel like I need to explain myself a bit better.
My gateway is pfsense on 10.0.1.19
I have two local DNS servers, both Windows DNS on an active domain which are synced. These are 10.0.1.30 and 10.0.1.22.These DNS servers both forward to Google DNS, if it can't resolve it.
This has been my setup for months, all my machines work fine, always resolving websites and local services.
The only issue I have noticed is this wifi calling DNS request made by android. While monitoring it with wireshark all over DNS queries were made to 10.0.1.30 with the correct mac address. I downloaded a nslookup tool for Android and when requesting the same host through that the packet was correct and went to the correct DNS server with the correct mac address.
When I said I'm not saying you're incorrect but earlier, I wasn't disputing the MACs only working locally, just the duplicate ips.
I honestly think that this is a bug in Androids implementation of Wifi calling, because my girlfriend iPhone has always consistently worked (with my local DNS servers) with EE Wifi Calling. It's only been my android phone that's had any issues. It seems there's a bug where this one call gets the ip of the DNS server and the mac of the gateway server mixed up and uses the wrong combination. I think this one call is special because it's a core built in service.
I'm really happy to be wrong and to find a solution though. But that's my thinking at the moment. This bug could be easily missed as 90% of home users won't run a local DNS so the DNS MAC will match the gateway MAC.
Here is my ARP cache in pfsense. https://imgur.com/6X6LU5g
Honestly I want to be wrong because an Android bug is going to be a PITA to get fixed. Anyone think I've misunderstood or am wrong?
Cheers
(also sorry for bad spelling, on mobile)
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Well if your Windows DNS Servers forward to google for global resolution I don't see where pfSense fits into the picture.
MAC addresses really have nothing to do with your problem unless, as has been said, you have an IP address conflict. Just forget about MAC addresses.
It really sounds like you need to realize a DNS strategy, get it working, then make sure all your devices are configured to use it.
Is the working iPhone configured to use the same DNS servers as the broken android phone?
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Well if your Windows DNS Servers forward to google for global resolution I don't see where pfSense fits into the picture.
MAC addresses really have nothing to do with your problem unless, as has been said, you have an IP address conflict. Just forget about MAC addresses.
It really sounds like you need to realize a DNS strategy, get it working, then make sure all your devices are configured to use it.
Is the working iPhone configured to use the same DNS servers as the broken android phone?
Yes, the iPhone has 10.0.1.30 and 10.0.1.22 as DNS servers and works perfectly, as does every other computer on the network. The only reason I bring up mac addresses is because the broken DNS packet as seen via wireshark has the wrong mac address so the DNS server isn't recieving the packet (i'm right in the assumption that no matter what the ip address is, NIC will ignore packets sent to it with a different mac address aren't I?)
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"NIC will ignore packets sent to it with a different mac address aren't I?)"
What?? Post up this sniff showing what you think is a wrong mac..
In your sniff there was NO answer to your queries.. No shit if your dns does not answer you can not look up stuff..
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"NIC will ignore packets sent to it with a different mac address aren't I?)"
What?? Post up this sniff showing what you think is a wrong mac..
In your sniff there was NO answer to your queries.. No shit if your dns does not answer you can not look up stuff..
Ive attached the traces
In the Onlythatdnsrequestbeingignored.png you can see that the DNS server is happily responding to every other DNS request coming from the android phone.
The workingdns image shows a packet being sent to 10.0.1.30 with its correct mac address, so the dns server responds.
The brokendns image shows the only packet thats broken. The only difference is the MAC address (which is my gateway not the dns server).
I put Microsoft DNS in debugging mode, which logs all requests, and it never even sees the broken DNS packet (because, i assume, the NIC ignores it as it has the incorrect MAC address)
See what I mean? This seems like unusual behaviour from my android device.
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What device do you own that is this mac?
6C:0B:84:08:67:34 I show it as Universal Global Scientific Industrial Co.,Ltd.
Clearly if your windows dns server is at 00:15:5d:01:f4:01 then no shit another box that is not running dns is not going to answer. You most likely have something that has the same IP 10.0.1.30 as your windows dns server is the most likely issue.
Is it this company http://www.usish.com/english/overview.asp look up what they make and what device you have of theirs.
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What device do you own that is this mac?
6C:0B:84:08:67:34 I show it as Universal Global Scientific Industrial Co.,Ltd.
Clearly if your windows dns server is at 00:15:5d:01:f4:01 then no shit another box that is not running dns is not going to answer. You most likely have something that has the same IP 10.0.1.30 as your windows dns server is the most likely issue.
Is it this company http://www.usish.com/english/overview.asp look up what they make and what device you have of theirs.
No, the windows box is at 6C:0B:84:08:67:34 (10.0.1.30). Thats the mac of the integrated Intel NIC on the motherboard.
The 00:15:5d:01:f4:01 mac address is that of pfsense (gateway) which is running on ip 10.0.1.19.
There is no ip conflict between them, both their IPs are static, and I posted my ARP Cache earlier and no MACs are duplicated.
That's why I'm at a loss
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Dude clearly 00:15:5d is a microsoft mac…
MAC Address Details
Company
Microsoft Corporation
Address
Redmond WA 98052-8300
UNITED STATES
Range
00:15:5D:00:00:00 - 00:15:5D:FF:FF:FF
Type
IEEE MA-LAnd clearly from your sniff your sending traffic for 10.0.1.30 to that MAC...
if your saying your windows box nic is that global universal company... That what is the microsoft mac device??
Post up your ifconfig from your pfsense box, and y our ipconfig /all from your windows machine running dns..
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Dude clearly 00:15:5d is a microsoft mac…
MAC Address Details
Company
Microsoft Corporation
Address
Redmond WA 98052-8300
UNITED STATES
Range
00:15:5D:00:00:00 - 00:15:5D:FF:FF:FF
Type
IEEE MA-LAnd clearly from your sniff your sending traffic for 10.0.1.30 to that MAC...
if your saying your windows box nic is that global universal company... That what is the microsoft mac device??
Post up your ifconfig from your pfsense box, and y our ipconfig /all from your windows machine running dns..
The reason why pfsense has a microsoft MAC is because it's a VM and that's a software NIC which is teamed with 3 NICS and LACP'ed at the router level. The 10.0.1.30 DNS Server is a physical server. 10.0.1.22 is a VM.
pfsense:
$ ifconfig pflog0: flags=100 <promisc>metric 0 mtu 33144 pfsync0: flags=0<> metric 0 mtu 1500 syncpeer: 224.0.0.240 maxupd: 128 defer: on syncok: 1 lo0: flags=8049 <up,loopback,running,multicast>metric 0 mtu 16384 options=600003 <rxcsum,txcsum,rxcsum_ipv6,txcsum_ipv6>inet 127.0.0.1 netmask 0xff000000 inet6 ::1 prefixlen 128 inet6 fe80::1%lo0 prefixlen 64 scopeid 0x3 nd6 options=21 <performnud,auto_linklocal>enc0: flags=0<> metric 0 mtu 1536 nd6 options=21 <performnud,auto_linklocal>hn0: flags=8843 <up,broadcast,running,simplex,multicast>metric 0 mtu 1500 options=18 <vlan_mtu,vlan_hwtagging>ether 00:15:5d:01:f4:00 inet6 fe80::215:5dff:fe01:f400%hn0 prefixlen 64 scopeid 0x5 nd6 options=21 <performnud,auto_linklocal>hn1: flags=8843 <up,broadcast,running,simplex,multicast>metric 0 mtu 1500 options=18 <vlan_mtu,vlan_hwtagging>ether 00:15:5d:01:f4:01 inet6 fe80::215:5dff:fe01:f401%hn1 prefixlen 64 scopeid 0x6 inet 10.0.1.19 netmask 0xffffff00 broadcast 10.0.1.255 nd6 options=21 <performnud,auto_linklocal>pppoe2: flags=88d1 <up,pointopoint,running,noarp,simplex,multicast>metric 0 mtu 1492 inet6 fe80::215:5dff:fe01:f400%pppoe2 prefixlen 64 scopeid 0x7 inet <<myip>> --> 195.166.130.211 netmask 0xffffffff nd6 options=21 <performnud,auto_linklocal>ovpns1: flags=8051 <up,pointopoint,running,multicast>metric 0 mtu 1500 <<omitted>> ovpns2: flags=8051 <up,pointopoint,running,multicast>metric 0 mtu 1500 <<omitted>> ovpnc3: flags=8051 <up,pointopoint,running,multicast>metric 0 mtu 1500 <<omitted>> ovpnc4: flags=8051 <up,pointopoint,running,multicast>metric 0 mtu 1500 <<omitted>> ovpnc5: flags=8051 <up,pointopoint,running,multicast>metric 0 mtu 1500 <<omitted>></omitted></up,pointopoint,running,multicast></omitted></up,pointopoint,running,multicast></omitted></up,pointopoint,running,multicast></omitted></up,pointopoint,running,multicast></omitted></up,pointopoint,running,multicast></performnud,auto_linklocal></myip></up,pointopoint,running,noarp,simplex,multicast></performnud,auto_linklocal></vlan_mtu,vlan_hwtagging></up,broadcast,running,simplex,multicast></performnud,auto_linklocal></vlan_mtu,vlan_hwtagging></up,broadcast,running,simplex,multicast></performnud,auto_linklocal></performnud,auto_linklocal></rxcsum,txcsum,rxcsum_ipv6,txcsum_ipv6></up,loopback,running,multicast></promisc>10.0.1.30
C:\Windows\system32>ipconfig /all Windows IP Configuration Host Name . . . . . . . . . . . . : Gibson Primary Dns Suffix . . . . . . . : mydomain.private Node Type . . . . . . . . . . . . : Hybrid IP Routing Enabled. . . . . . . . : No WINS Proxy Enabled. . . . . . . . : No DNS Suffix Search List. . . . . . : mydomain.private Ethernet adapter vEthernet (Internal): (this is a private VM network to some VMs) Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Hyper-V Virtual Ethernet Adapter #2 Physical Address. . . . . . . . . : 00-15-5D-01-F4-0A DHCP Enabled. . . . . . . . . . . : No Autoconfiguration Enabled . . . . : Yes IPv4 Address. . . . . . . . . . . : 192.168.0.1(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.255.0 Default Gateway . . . . . . . . . : NetBIOS over Tcpip. . . . . . . . : Enabled Ethernet adapter Integrated: (this is a physical onboard NIC just for 10.0.1.30) Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Intel(R) Ethernet Connection I217-LM Physical Address. . . . . . . . . : 6C-0B-84-08-67-34 DHCP Enabled. . . . . . . . . . . : No Autoconfiguration Enabled . . . . : Yes IPv4 Address. . . . . . . . . . . : 10.0.1.30(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.255.0 Default Gateway . . . . . . . . . : 10.0.1.19 DNS Servers . . . . . . . . . . . : 127.0.0.1 10.0.1.22 NetBIOS over Tcpip. . . . . . . . : Enabled Tunnel adapter isatap.{CD48BF58-A900-4A8C-917E-6E0083ABD4E4}: Media State . . . . . . . . . . . : Media disconnected Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Microsoft ISATAP Adapter Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0 DHCP Enabled. . . . . . . . . . . : No Autoconfiguration Enabled . . . . : Yes Tunnel adapter isatap.{D7362D7E-EA03-4337-8329-58F19F230FE7}: Media State . . . . . . . . . . . : Media disconnected Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Microsoft ISATAP Adapter #3 Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0 DHCP Enabled. . . . . . . . . . . : No Autoconfiguration Enabled . . . . : Yes
