[Dnsmasq-discuss] android client does not check ip address with DHCPREQUEST

[Inigo de la Fuente]

Hi All,

I have performed several test and already have opened one thread about this 
issue. I have seen unexpected behavior on android when DHCPv4 client tries to 
reuse a previously allocated network address and this address is unavailable on 
the server.

The test steps are the following:

  1.  Set the range of DHCP leases to only 1. Until now, DHCP can only lease 
one address.
  2.  Connect a device and get the only IPv4 address lease available then 
disconnect.
  3.  On the server dnsmasq leases file, replace the IPv4 lease and give the 
address to other machine.
  4.  Reconnect the device on point 1.


Basically on windows and IOS I can see that the first message on the DHCP 
client-server communication is a DHCPREQUEST sent by the client with the IPV4 
address that wants to reuse. Then, the server respond with a DHCPNAK indicating 
the lease is not available anymore on the server. After that the client tries 
to get a new IPV4 but is not possible because no IPV4 range is available. (the 
only available address is assigned).
This is the correct behavior indicated on RFC1531

However, on Android the DHCPv4 client does not use DHCPREQUEST and then it 
reuses the address even when that address has been reassigned to other machine.

Did someone experience that?

Regards and thanks in advance




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Re: [Dnsmasq-discuss] [DHCPV4] android devices issue makes able to use a reserved ipv4 address in dnsmasq

[Inigo de la Fuente]

Hey Geert,

Could you explain why the different behavior between windows and android.

Regards

---
Met vriendelijke groet / With kind regards,

Iñigo De La Fuente
Sr. Software Designer
[ict logo]

Machine & Systems

Visiting address: Prof. Dr. Dorgelolaan 30, 5613 AM, Eindhoven, The Netherlands
E inigo.de.la.fue...@ict.nl
M +31625733268
W www.ict.eu

Chamber of Commerce no. 24254385





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[Dnsmasq-discuss] [DHCPV4] ANDROID DEVICES ISSUE MAKES ABLE TO USE A RESERVED IPV4 ADDRESS IN DNSMASQ

[Inigo de la Fuente]

Hi all,

I have a question regarding to DHCPv4 leases.
Doing some tests I have faced a possible android issue that I want to share 
with you.

1.- I set the DHCP range of ipv4 address from 192.168.72.51 to 192.168.72.150 
in dnsmasq.conf.
2.- One windows pc is connected and get an ipv4 lease (192.168.72.65)
3.- One android device is connected and get an ipv4 lease (192.168.72.133)
4.- stop dnsmasq and remove all entries in dhcp.leases
5.- add dummy entries to dhcp.leases file till there is not any address 
available in the dhcp range and start dnsmasq again.
6.-  windows pc is not able to obtain an ipv4 lease because all are occupied. 
Ping is not possible
7.- android device 'seems' to be able to use the saved leased ipv4 
(192.168.72.133). Ping is possible

Here the output of dnsmasq at step 7:
"dnsmasq-dhcp: 93920162 available DHCP range: 10.173.190.51 -- 10.173.190.150
dnsmasq-dhcp: 93920162 vendor class: HUAWEI:android:ANE
dnsmasq-dhcp: 93920162 client provides name: HUAWEI_P20_lite-9a7e63d7d
dnsmasq-dhcp: 93920162 DHCPDISCOVER(eth1) 00:be:3b:02:c1:02 no address available
dnsmasq-dhcp: 93920162 available DHCP range: 10.173.190.51 -- 10.173.190.150
dnsmasq-dhcp: 93920162 vendor class: HUAWEI:android:ANE
dnsmasq-dhcp: 93920162 client provides name: HUAWEI_P20_lite-9a7e63d7d
dnsmasq-dhcp: 93920162 DHCPDISCOVER(eth1) 00:be:3b:02:c1:02 no address available
dnsmasq-dhcp: 93920162 available DHCP range: 10.173.190.51 -- 10.173.190.150"

Why my device is able to ping with the last saved leased ipv4 address even if 
this address is reserved in dhcp.leases file?

Best Regards




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[Dnsmasq-discuss] DHCPv6 does not update ipv6 timestamp lease times

[Inigo de la Fuente]

I am using dnsmasq 2.78.

Doing some test I have connect 3 different devices and when reading dhcp.leases 
file I found that only the timestamp of the ipv4 leases files are updated not 
for ipv6.

Why does not update timestamp for ipv6 leases?

this is my dnsmasq.conf:
"
dhcp-authoritative
domain-needed
localise-queries
read-ethers
bogus-priv
expand-hosts
server=/lan/
dhcp-leasefile=/data/wlanman/dhcp.leases
resolv-file=/etc/resolv.conf
addn-hosts=/tmp/hosts
stop-dns-rebind
rebind-localhost-ok
dhcp-broadcast=tag:needs-broadcast
interface=eth1
enable-ra
no-dhcp-interface=rmnet_data0
dhcp-range=lan,10.173.190.51, 10.173.190.150, 255.255.255.0, 72h
dhcp-range=lan,fd30:e08e:c031:0020::33, fd30:e08e:c031:0020::96, 64,  ra-only, 
72h

dhcp-host=40:a3:cc:7d:9d:30,10.173.190.33
dhcp-host=id:00:01:00:01:21:EF:26:71:8C:EC:4B:E5:28:6B,[fd30:e08e:c031:0020::30]
"

Hope someone can help me.

Regards




---
Met vriendelijke groet / With kind regards,

Iñigo De La Fuente
Sr. Software Designer
[ict logo]

Machine & Systems

Visiting address: Prof. Dr. Dorgelolaan 30, 5613 AM, Eindhoven, The Netherlands
E inigo.de.la.fue...@ict.nl
M +31625733268
W www.ict.eu

Chamber of Commerce no. 24254385





 Disclaimer 
This email and any files transmitted may contain proprietary and confidential 
information of ICT Group N.V. or any of its subsidiaries ("ICT") and is 
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received this message in error or are not the intended or named recipient(s) of 
this message, please immediately notify the sender by return and delete this 
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those of its author and do not necessarily represent those of ICT. You are 
hereby notified that unauthorized disclosure, use, dissemination, forwarding, 
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