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author | Simon Kelley <simon@thekelleys.org.uk> | 2017-02-19 22:13:36 +0000 |
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committer | Simon Kelley <simon@thekelleys.org.uk> | 2017-02-19 22:13:36 +0000 |
commit | 54bb3639d4d58ebb5502874bb024745d14ba1a62 (patch) | |
tree | dd6b074d524a8aefad97f958a11bbf7a11283ba1 /FAQ | |
parent | fca008d8d486b3071eb2c1e00dba2d8d963b19dd (diff) | |
download | dnsmasq-54bb3639d4d58ebb5502874bb024745d14ba1a62.tar.gz |
Update FAQ to fix a couple of dead links.
Thanks to Federico Bianchi for reporting this.
Diffstat (limited to 'FAQ')
-rw-r--r-- | FAQ | 60 |
1 files changed, 58 insertions, 2 deletions
@@ -320,8 +320,18 @@ A: Yes, new releases of dnsmasq are always announced through Q: What does the dhcp-authoritative option do? -A: See http://www.isc.org/files/auth.html - that's - for the ISC daemon, but the same applies to dnsmasq. +A: The DHCP spec says that when a DHCP server recieves a renewal request + from a client it has no knowledge of, it should just ignore it. + This is because it's supported to have more than one DHCP server + on a network, and another DHCP server may be dealing with the client. + This has the unfortunate effect that when _no_ DHCP replies to + the client, it takes some time for the client to time-out and start + to get a new lease. Setting this option makes dnsmasq violate the + standard to the extent that it will send a NAK reply to the client, + causing it to immediately start to get a new lease. This improves + behaviour when machines move networks, and in the case that the DHCP + lease database is lost. As long as there are not more tha one DHCP + server on the network, it's safe to enable the option. Q: Why does my Gentoo box pause for a minute before getting a new lease? @@ -349,6 +359,7 @@ A: By default, the identity of a machine is determined by using the method for setting the client-id varies with DHCP client software, dhcpcd uses the "-I" flag. Windows uses a registry setting, see http://www.jsiinc.com/SUBF/TIP2800/rh2845.htm + Addendum: From version 2.46, dnsmasq has a solution to this which doesn't involve setting client-IDs. It's possible to put more than one MAC @@ -361,6 +372,51 @@ Addendum: constraint: if you configure multiple MAC addresses and violate this rule, bad things will happen. +Addendum-II: The link above is dead, the former contents of the link are: + +------------------------------------------------------------------------------ +How can I keep the same DHCP client reservation, if the MAC address changes? + +When you reserve an IP address for a DHCP client, you provide the +MAC address of the client's NIC. + +It is possible to use a custom identifier, which is sent as +option 61 in the client's DHCP Discover and Request packet. + +The DhcpClientIdentifier is a REG_DWORD value that is located at: + +Windows NT 4.0 SP2+ + +HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\<Adapter Name>'X'\Parameters\Tcpip + +where <Adapter Name> is the NIC driver name and 'X' is the number of the NIC. + +Windows 2000 + +HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\TcpIp\Parameters\Interfaces\<NIC GUID> + +where <NIC GUID> is the GUID of the NIC. + +The valid range of data is 0x0 - 0xFFFFFFFF. The custom identifier is send as 4 bytes, +8 hexadecimal character, in groups of 2 hexadecimal characters, with the groups being +sent in reverse order. If the custom identifier is less than 8 hexadeciaml characters, +it is zero padded at the end. Examples: + +Custom Client Client Reservation +Identifier on DHCP Server +12345678 78563412 +123456 56341200 +1234 34120000 +1234567 67452301 +12345 45230100 +123 23010000 +A18F42 428FA100 +CF432 32F40C00 +C32D1BE BED1320C + +------------------------------------------------------------------------------------------------------- + + Q: Can dnsmasq do DHCP on IP-alias interfaces? A: Yes, from version-2.21. The support is only available running under |