[Dnsmasq-discuss] DHCP Relay, assign address from other vlan, with no dhcp listening on it

SpiderX spiderx at spiderx.dp.ua
Mon Sep 12 08:17:15 BST 2011


Thanks for reply.
I have just tried this.
conflg:
#dhcp-range=tag:vlan-2-port-16,10.1.2.2,10.1.2.245,255.255.255.0,10.1.2.255,10m
#dhcp-range=tag:#vlan-2-port-16,172.16.33.2,172.16.33.249,255.255.255.0,10m
dhcp-host=48:5b:39:36:a2:73,10.1.2.100

Absolutely nothing happened with such config, dnsmasq did nothing.
I saw DHCPDISCOVER in vlan1033 at the same time.
When I commented out 'dhcp-range=tag:#vlan-2-port-16,172.16.33.2....',
dnsmasq tried assign address from
range 172.16.33.2-172.16.33.249.
log:
Sep 12 13:00:45 dnsmasq-dhcp[11194]: 2517313542 available DHCP range:
172.16.33.2 -- 172.16.33.249
Sep 12 13:00:45 dnsmasq-dhcp[11194]: 2517313542 client provides name: laptop
Sep 12 13:00:45 dnsmasq-dhcp[11194]: 2517313542 DHCPDISCOVER(vlan1033)
172.16.33.121 48:5b:39:36:a2:73 no address available
Sep 12 13:00:48 dnsmasq-dhcp[11194]: 2517313542 available DHCP range:
172.16.33.2 -- 172.16.33.249
Sep 12 13:00:48 dnsmasq-dhcp[11194]: 2517313542 client provides name: laptop
Sep 12 13:00:48 dnsmasq-dhcp[11194]: 2517313542 DHCPDISCOVER(vlan1033)
172.16.33.121 48:5b:39:36:a2:73 no address available

With such results I assume that dhcp relay with dnsmasq don't work at all.
Any ideas?

On Sat, Sep 10, 2011 at 11:09 PM, Shantanu Gadgil
<shantanugadgil at yahoo.com> wrote:
>
> Hi Vladimir,
> I assume you have tried with a simpler setup:
> *without tags in the range part*.
> Use the 'static' dhcp range method to assign the IPs based on mac address.
>
> Regards,
> Shantanu
>
> --- On Sat, 9/10/11, SpiderX <spiderx at spiderx.dp.ua> wrote:
>
> > From: SpiderX <spiderx at spiderx.dp.ua>
> > Subject: [Dnsmasq-discuss] DHCP Relay, assign address from other vlan, with no dhcp listening on it
> > To: dnsmasq-discuss at lists.thekelleys.org.uk
> > Date: Saturday, September 10, 2011, 2:58 PM
> > Hello, my name is Vladimir.
> > I'm trying to setup dnsmasq to work in DHCP Relay (RFC3046)
> > environment.
> > Compiled with tftp, dhcp support and without dbus, ipv6,
> > idn.
> >
> > topology:
> > client (dhcp,10.1.2.0/24) — l2 switch (172.16.33.50) —
> > server with
> > dnsmasq (172.16.30.252)
> >
> > server:
> > ip a:
> > 5: vlan0002 at eth1: <BROADCAST,MULTICAST,UP,LOWER_UP>
> > mtu 1500 qdisc
> > noqueue state UP
> >     link/ether 00:1e:67:02:ad:6a brd
> > ff:ff:ff:ff:ff:ff
> >     inet 10.1.2.250/24 brd 10.1.2.255 scope
> > global vlan0002
> > 6: vlan0003 at eth1: <BROADCAST,MULTICAST,UP,LOWER_UP>
> > mtu 1500 qdisc
> > noqueue state UP
> >     link/ether 00:1e:67:02:ad:6a brd
> > ff:ff:ff:ff:ff:ff
> >     inet 10.1.3.250/24 brd 10.1.3.255 scope
> > global vlan0003
> > ..........lots of vlan......
> > 88: vlan1033 at eth1: <BROADCAST,MULTICAST,UP,LOWER_UP>
> > mtu 1500 qdisc
> > noqueue state UP
> >     link/ether 00:1e:67:02:ad:6a brd
> > ff:ff:ff:ff:ff:ff
> >     inet 172.16.33.252/24 scope global vlan1033
> > sysctl:
> > net.ipv4.ip_forward=1
> >
> > config:
> > dhcp-circuitid=set:vlan-2-port-16,00:04:00:02:00:10
> > dhcp-option=option:router,10.1.2.250
> > dhcp-range=tag:vlan-2-port-16,10.1.2.2,10.1.2.245,255.255.255.0,10.1.2.255,10m
> > dhcp-range=tag:#vlan-2-port-16,172.16.33.2,172.16.33.249,255.255.255.0,10m
> > dhcp-leasefile=/var/lib/misc/dnsmasq.leases
> > dhcp-authoritative
> > log-dhcp
> > log-facility=/var/log/dnsmasq.log
> >
> > log:
> > Sep 10 14:37:28 dnsmasq[20380]: started, version 2.58
> > cachesize 150
> > Sep 10 14:37:28 dnsmasq[20380]: compile time options:
> > no-IPv6
> > GNU-getopt no-DBus i18n DHCP TFTP no-conntrack IDN
> > Sep 10 14:37:28 dnsmasq-dhcp[20380]: DHCP, IP range
> > 172.16.33.2 --
> > 172.16.33.249, lease time 10m
> > Sep 10 14:37:28 dnsmasq-dhcp[20380]: DHCP, IP range
> > 10.1.2.2 --
> > 10.1.2.245, lease time 10m
> > Sep 10 14:37:28 dnsmasq[20380]: reading /etc/resolv.conf
> > Sep 10 14:37:28 dnsmasq[20380]: using nameserver
> > 91.193.69.4#53
> > Sep 10 14:37:28 dnsmasq[20380]: bad address at /etc/hosts
> > line 2
> > Sep 10 14:37:28 dnsmasq[20380]: read /etc/hosts - 1
> > addresses
> > Sep 10 14:37:39 dnsmasq-dhcp[20380]: 3769651775 available
> > DHCP range:
> > 172.16.33.2 -- 172.16.33.249
> > Sep 10 14:37:39 dnsmasq-dhcp[20380]: 3769651775 client
> > provides name: laptop
> > Sep 10 14:37:39 dnsmasq-dhcp[20380]: 3769651775
> > DHCPDISCOVER(vlan1033)
> > 172.16.33.121 48:5b:39:36:a2:73 no address available
> > Sep 10 14:37:44 dnsmasq-dhcp[20380]: 3769651775 available
> > DHCP range:
> > 172.16.33.2 -- 172.16.33.249
> > Sep 10 14:37:44 dnsmasq-dhcp[20380]: 3769651775 client
> > provides name: laptop
> > Sep 10 14:37:44 dnsmasq-dhcp[20380]: 3769651775
> > DHCPDISCOVER(vlan1033)
> > 172.16.33.121 48:5b:39:36:a2:73 no address available
> >
> > So, dnsmasq got a DHCPDISCOVER message in vlan1033 with
> > option82 that
> > match tag vlan-2-port-16.
> > Client doesn't get a lease because of 'tag:#vlan-2-port-16'
> > in last
> > dhcp-range, that's why I assume that tag vlan-2-port-16 is
> > matched.
> > The problem is dnsmasq completely ignore first range
> > 'tag:vlan-2-port-16,10.1.2.2....', and always try to assign
> > address
> > from range 172.16.33.0/24.
> > I think that happends because there is not ip address from
> > network
> > 10.1.2.0/24 on vlan1033 unlike ip address 172.16.33.252.
> > So, I assume that dnsmasq assigns address from ranges that
> > match ip
> > addresses on interfaces dhcp packets come from.
> > How dhcp relay supposed to work with such dnsmasq
> > behavior?
> >
> > _______________________________________________
> > Dnsmasq-discuss mailing list
> > Dnsmasq-discuss at lists.thekelleys.org.uk
> > http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
> >
>
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