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On 23/06/16 21:02, John Groves (jgroves) wrote: > I'm a long-time dnsmasq user, but first-time poster. I can't > imagine that this hasn't been discussed before, but I wasn't able > to come up with search terms to find it. > > This arises because we are creating and destroying VMs like crazy > for automated software testing. The VMs are using dynamic-range > addresses, and every time a VM is rebooted it gets a new address, > even if there is a valid existing lease. And we see leases for the > same mac address accumulating in the leases file, like this: > > 1466722310 52:54:00:51:e7:ad 10.114.5.186 localhost > ff:00:51:e7:ad:00:01:00:01:1e:fe:ec:44:52:54:00:51:e7:ad 1466722212 > 52:54:00:51:e7:ad 10.114.5.185 * > ff:00:51:e7:ad:00:01:00:01:1e:fe:eb:e2:52:54:00:51:e7:ad 1466719093 > 52:54:00:51:e7:ad 10.114.5.184 * > ff:00:51:e7:ad:00:01:00:01:1e:fe:df:b3:52:54:00:51:e7:ad 1466718818 > 52:54:00:6f:8c:2a 10.114.5.227 * > ff:00:6f:8c:2a:00:01:00:01:1e:fe:de:9f:52:54:00:6f:8c:2a 1466715993 > 52:54:00:4a:54:e7 10.114.5.179 * > ff:00:4a:54:e7:00:01:00:01:1e:fe:d3:96:52:54:00:4a:54:e7 > > Is there a way to coax dnsmasq to give out an address matching the > still-valid lease, if any? > > FYI the VMs are mostly Fedora 2[234] and RHEL7 > > The changing addresses are a challenge for our test automation... > > Thanks, John Groves If the DHCP provides a client-id, that's used to identify the client in preference to the MAC address. The client-id is the last field on each line of the lease-file, and we can see the client-ids for each lease associated with a single MAC address are different in a couple of bytes. These bytes are probably generated from the system time. To fix this, build your VMs to not provide a client-id, or one completely determined by the MAC address. You can also configure dnsmasq to ignore the client-id with something like dhcp-host=52:54:00:*:*:*,id:* Cheers, Simon. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIcBAEBCAAGBQJXbFjfAAoJEBXN2mrhkTWiej4P/20kUt94wBuhowgrxg0VOBrP PV2uj9XTdpNG5Ys9Mb7pgFzxlwx7Hus2d8g0JnaPjo0CPK4eUDe8qhKKZi7ppL7k kL9ZFmMVBVD63x5NRPcGpPMQytQJt0Fi89lrvTXf+y+TOv/MsmEbOjSh5euIA9N7 rCNDGVuykgSj6MBKO4kEd0T6w/hrouEIJEFnXIpo5Bbav9FM4+IB+CPbfvrG16vq zgf1R4Oh3UoCS4QTHlbV1C7xVAAw2jckRK+Rc/F5aN+i+HpSiheS3t8kk24gOB+m xrar1Bt8lzbeY1RCZRgQkX9UJrhN13zpfuVQ4OHSqomj1Mtgs6G9Saa0vYmd0hI7 A/Gg2mKf1FeUq7uudJ/V4znS/nTRfVZaPZRSMb+M0Q/rzPFUx6+nzBDRBwDqFB01 zXg7Zj8a1f0JQ2BL0VIA994OLDznZYieCVMxWBBMSKgpwsgAyolY5Zak6c8izhkF dGG9JTv7C2FMr/L3Pl4IifntfURxgTH3XkhRKgSZsJza5MO45GbOeJNy4t+b4A09 xzv1EjPj+hyI1QmzTqGBdPvywV4jb+v2Lmfg+nHL0W0LwMv7q5yCFCsNq9k0CMW9 HxZsx1P5KVWm91DMO1bk2DfouWNUr1v3GIux/5gPaZxUGu7Ve03L28ZIMIh+ZPJ4 1WD8PzsiJSyLnakOiLX6 =GFIb -----END PGP SIGNATURE----- _______________________________________________ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss