-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 On 25/08/15 07:33, Harald Dunkel wrote: > Hi folks, > > AFAICS there is no way for dnsmasq to make a client stop using an > IPv4 address if the lease expires. Esp. some Apple and Android > devices seem to play dirty. > > Sure, they accept the new IP address via DHCP and start using it, > but the old address is not dropped. Result is > > : Aug 25 08:08:04 gate /bsd: arp info overwritten for 10.10.123.204 > by 00:1f:f3:08:xx:xx on re1 Aug 25 08:08:25 gate /bsd: arp info > overwritten for 10.10.123.204 by 6c:94:f8:e2:yy:yy on re1 Aug 25 > 08:20:12 gate /bsd: arp info overwritten for 10.10.123.204 by > 00:1f:f3:08:xx:xx on re1 Aug 25 08:20:25 gate /bsd: arp info > overwritten for 10.10.123.204 by 6c:94:f8:e2:yy:yy on re1 Aug 25 > 08:20:26 gate /bsd: arp info overwritten for 10.10.123.204 by > 00:1f:f3:08:xx:xx on re1 Aug 25 08:21:55 gate /bsd: arp info > overwritten for 10.10.123.204 by 6c:94:f8:e2:yy:yy on re1 : > > This is from /var/log/messages on the dnsmasq server. Of course, > there is only one lease for this IP address (I checked). I wonder > if dnsmasq could detect and work around this conflict? >
Dnsmasq does the check which the standards require, which is to send an ICMP ping (echo request) to the address it's about to allocate. The fact that the client doesn't respond would seem to indicate that the clients are NOT using IP addresses after the lease has expired. My guess is that what's happening here is that the ARP-table entry on the server persisting after the lease expires. When the IP address is given to a new client, dnsmasq updates the ARP table, and those are just warnings that the ARP table for 10.10.123.204 is being overwritten. Cheers, Simon. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIcBAEBCAAGBQJV3NumAAoJEBXN2mrhkTWiYqkP/3E/9JDKSG/Tjhzn3JnIZCdr BTjdRhRGv1b7e7NiNjMKRIoitGILMbmTSHYS9vhV1T8QjZF52KMKhHHY+dZ2siKd Zj7sG+be1tcg/l1/zfL4aqMW0QUEGLnuXAJGeC5PexRy0rdPN16F9G5SfyTvRQo2 0lNklMICBtXQejIRNuZJHyAZVRMmcmKtTisfrPVSOx+ORLEFfw2U/rPS551apuTD 9GYwbaQQI9abkw2undtG9nEtHMtkXD6nFp6FRtyGVVJg6dv11k+MwfR5oW1y0jZh FiIjkPUhSosu66AzgcDnzeUtkObbnLJOWOkyxWhwk663fkV/9AjTGecp1wjWXD0o +cjv06lwvHYr+ZNt8Kn2m9GDQAvSCI/hC27S3/v20ZkAA+uP0+9zZbVXXcop34NQ 94ADyRvp7jz8DGPoMIYuo8iC5ibRc6Dq2wNfl7zx0BaDsoe+R3g+ipkaeXInx63x z4MbgRJM20T2xAz2s4CY9nYNF/Qq1+AeiLpFEAxo7qYzORS7rnbRphDrI4EBlXML CpIDHwvJA1W9+PSMyFoONa+pTj1SfHGF3uNt+7/jKaerD3pUcqg0q+AiSUVjxgbm /tFopTjBbTa34Ix0Gx9kGJahAExI3ePqtUZSR6T5gOKTieFc7x6Fw1t+2w2dCTXZ uh01HuHpVJu9XkLP6qQN =qkbZ -----END PGP SIGNATURE----- _______________________________________________ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
