Problems with DHCP using VLANs
Tim Gavin
livewire98801 at gmail.com
Wed Aug 26 18:23:11 UTC 2009
I did a short capture and didn't see any. I'm running a longer one
now to be sure.
On Wed, Aug 26, 2009 at 10:44, <dhcp at ugh.speedxs.nl> wrote:
> hi tim,
>
>> Beyond watching syslog for DHCP events on that interface, is there a
>> way to see DHCP packets coming in on that interface, or do I need to
>> capture with wireshark or something?
>
> tshark/tcpdump/snoop would be the best option. Just watch if you see any
> dhcp packets coming in on the right vlan-interface and that you are not
> capturing the whole interface.
>
> also if you have a test setup you could try running strace/truss on the
> dhcp process to see if it processes the dhcp packet.
>
>> Thanks for your quick response,
>
> no problem.
>
> hilmar
>
>>
>> Tim
>>
>> On Wed, Aug 26, 2009 at 10:34, <dhcp at ugh.speedxs.nl> wrote:
>>> Hi tim,
>>>
>>> for starters can you tell us which kernel version you are using and if
>>> you see dhcp packets coming in on the vlan interface.
>>>
>>> Also is the dhcp being relayed before it reaches the end point ( eg ip
>>> helper ).
>>>
>>> regards hilmar
>>>
>>> Tim Gavin wrote:
>>>> I work for an ISP. When I came in, there were three windows DHCP
>>>> servers running. I have since set up a Linux DHCP server running
>>>> Debian Etch to replace them.
>>>>
>>>> Currently, I have multiple VLANs running on that server, and the
>>>> server is running DHCP quite happily on one of the vlans. The problem
>>>> is that even though I can add new vlans all day long, I can't get
>>>> dhcpd to hand out addresses on them. Other communication on those
>>>> vlans works just fine though, I can ping, ssh, and download debian
>>>> updates just fine.
>>>>
>>>> I have found examples of what I'm doing and howtos and walkthroughs,
>>>> and as far as I can tell, I'm doing everything right. Syslog is not
>>>> showing any evidence that the requests are even coming in.
>>>>
>>>> I would appreciate any help or insight anyone can give me, I
>>>> desperately need to reclaim some of this hardware.
>>>>
>>>> Thanks,
>>>>
>>>> Tim
>>>>
>>>>
>>>>
>>>> -------------
>>>>
>>>> @dhcp:~$ cat /etc/network/interfaces
>>>> # This file describes the network interfaces available on your system
>>>> # and how to activate them. For more information, see interfaces(5).
>>>>
>>>> # The loopback network interface
>>>> auto lo
>>>> iface lo inet loopback
>>>>
>>>> # The primary network interface
>>>> #allow-hotplug eth0
>>>> #iface eth0 inet static
>>>>
>>>> #eth1 - Management
>>>> auto eth1
>>>> iface eth1 inet static
>>>> address 192.168.255.12
>>>> netmask 255.255.255.0
>>>>
>>>>
>>>> #############
>>>> #Vlan Config#
>>>> #############
>>>>
>>>> #VLAN 283
>>>> auto vlan283
>>>> #iface vlan283 inet static
>>>> # address xxx.xxx.xxx.194
>>>> # netmask 255.255.255.224
>>>> # mtu 1500
>>>> # vlan_raw_device eth0
>>>>
>>>>
>>>> #VLAN 285
>>>> auto vlan285
>>>> iface vlan285 inet static
>>>> address xxx.xxx.xxx.158
>>>> netmask 255.255.255.192
>>>> gateway xxx.xxx.xxx.129
>>>> mtu 1500
>>>> vlan_raw_device eth0
>>>>
>>>> #VLAN 287
>>>> auto vlan287
>>>> iface vlan287 inet static
>>>> address 172.16.32.2
>>>> netmask 255.255.240.0
>>>> mtu 1500
>>>> vlan_raw_device eth0
>>>>
>>>> #VLAN 288 - Grant Static
>>>> #auto vlan288
>>>> #iface vlan288 inet static
>>>> # address
>>>> # netmask 255.255.255.0
>>>> # mtu 1500
>>>> # vlan_raw_device eth0
>>>>
>>>> #VLAN 410
>>>> auto vlan410
>>>> iface vlan410 inet static
>>>> address 172.26.0.2
>>>> netmask 255.255.240.0
>>>> mtu 1500
>>>> vlan_raw_device eth0
>>>>
>>>>
>>>>
>>>>
>>>> -------------
>>>>
>>>> @dhcp:~$ cat /etc/dhcp3/dhcpd.conf
>>>>
>>>> ddns-update-style none;
>>>>
>>>> default-lease-time 600;
>>>> max-lease-time 7200;
>>>>
>>>> log-facility local7;
>>>>
>>>> #Interfaces
>>>> INTERFACES="vlan287 vlan283 vlan410";
>>>>
>>>>
>>>> #######################
>>>> #VLAN 287#
>>>> #######################
>>>>
>>>> subnet 172.16.32.0 netmask 255.255.240.0 {
>>>> range 172.16.33.1 172.16.46.254;
>>>> option domain-name-servers xxx.xxx.xxx.140, xxx.xxx.xxx.141;
>>>> option domain-name "company.com";
>>>> option routers 172.16.32.1;
>>>> option broadcast-address 172.16.47.255;
>>>> default-lease-time 43200;
>>>> max-lease-time 86400;
>>>> authoritative;
>>>> }
>>>>
>>>> ########################
>>>> #VLAN 283#
>>>> ########################
>>>>
>>>> subnet xxx.xxx.xxx.192 netmask 255.255.255.224 {
>>>> range xxx.xxx.xxx.195 xxx.xxx.xxx.205;
>>>> range xxx.xxx.xxx.207 xxx.xxx.xxx.208;
>>>> range xxx.xxx.xxx.216 xxx.xxx.xxx.217;
>>>> range xxx.xxx.xxx.221 xxx.xxx.xxx.221;
>>>> option domain-name-servers xxx.xxx.xxx.140, xxx.xxx.xxx.141;
>>>> option domain-name "company.com";
>>>> option routers xxx.xxx.xxx.193;
>>>> option broadcast-address xxx.xxx.xxx.223;
>>>> default-lease-time 43200;
>>>> max-lease-time 86400;
>>>> authoritative;
>>>> }
>>>>
>>>> host marshall {
>>>> hardware ethernet 00:0c:42:30:c9:f1;
>>>> fixed-address xxx.xxx.xxx.206;
>>>> }
>>>>
>>>>
>>>> ######################
>>>> #VLAN 410#
>>>> ######################
>>>>
>>>> subnet 172.26.0.0 netmask 255.255.240.0 {
>>>> range 172.26.1.1 172.26.1.254;
>>>> option domain-name-servers xxx.xxx.xxx.140, xxx.xxx.xxx.141;
>>>> option domain-name "company.com";
>>>> option routers 172.26.0.1;
>>>> option broadcast-address 172.26.15.255;
>>>> default-lease-time 43200;
>>>> max-lease-time 86400;
>>>> authoritative;
>>>> }
>>>>
>>>>
>>>> --------------
>>>>
>>>> @dhcp:~$ sudo cat /proc/net/vlan/*
>>>> VLAN Dev name | VLAN ID
>>>> Name-Type: VLAN_NAME_TYPE_PLUS_VID_NO_PAD
>>>> vlan285 | 285 | eth0
>>>> vlan287 | 287 | eth0
>>>> vlan410 | 410 | eth0
>>>>
>>>> vlan285 VID: 285 REORDER_HDR: 1 dev->priv_flags: 1
>>>> total frames received 1143047
>>>> total bytes received 71488781
>>>> Broadcast/Multicast Rcvd 0
>>>>
>>>> total frames transmitted 1126931
>>>> total bytes transmitted 83516369
>>>> total headroom inc 0
>>>> total encap on xmit 1126931
>>>> Device: eth0
>>>> INGRESS priority mappings: 0:0 1:0 2:0 3:0 4:0 5:0 6:0 7:0
>>>> EGRESSS priority Mappings:
>>>>
>>>> vlan287 VID: 287 REORDER_HDR: 1 dev->priv_flags: 1
>>>> total frames received 1868431
>>>> total bytes received 149664594
>>>> Broadcast/Multicast Rcvd 3215
>>>>
>>>> total frames transmitted 73624
>>>> total bytes transmitted 13580680
>>>> total headroom inc 0
>>>> total encap on xmit 73624
>>>> Device: eth0
>>>> INGRESS priority mappings: 0:0 1:0 2:0 3:0 4:0 5:0 6:0 7:0
>>>> EGRESSS priority Mappings:
>>>>
>>>> vlan410 VID: 410 REORDER_HDR: 1 dev->priv_flags: 1
>>>> total frames received 67467
>>>> total bytes received 3377190
>>>> Broadcast/Multicast Rcvd 0
>>>>
>>>> total frames transmitted 24
>>>> total bytes transmitted 1992
>>>> total headroom inc 0
>>>> total encap on xmit 24
>>>> Device: eth0
>>>> INGRESS priority mappings: 0:0 1:0 2:0 3:0 4:0 5:0 6:0 7:0
>>>> EGRESSS priority Mappings:
>>>> _______________________________________________
>>>> dhcp-users mailing list
>>>> dhcp-users at lists.isc.org
>>>> https://lists.isc.org/mailman/listinfo/dhcp-users
>>>
>
>
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