dhcrelay duplicated request
Klemen Sladic
gosturnca at gmail.com
Mon Jan 15 19:59:52 UTC 2018
Hi.
I am not sure about your environment, but I had similar problem on our
system.
We have a system with 2 Eth interfaces connected to internal on-board
Micrel switch.
I am not sure if this has any similarity with your setup, but here is mine
and it may
at least give you some ideas:
1. Unit1: DHCP client in VLAN 100.
2. Unit2: DHCP relay. This unit has 2 Eth Ports on internal switch.
|Unit1 | |Unit2 |
|br0.100| --VLAN100--> |DHCP relay|--to DHCPs->
|DHCPc | | |
The problem was, that the internal switch for the interface on Unit2 was
accepting VLAN100 and
also untagged traffic. As soon as I disabled untagged traffic for that port
in the switch on Unit2,
I did not get duplicated requests any more.
So, you should look for packets on your interfaces and find out which
interfaces kernel is broadcasting
them to. Probably they "leak" to more than one interface you'd like to.
Hope it helps.
RegK
On Tue, Jan 16, 2018 at 4:21 AM, IMMO WETZEL <IMMO.WETZEL at adtran.com> wrote:
> HI
>
>
>
> Why do I get duplicated request frames towards the dhcp server ?
>
> One as unicast from originator and one as unicast from the relay.
>
> Do I have to do some filtering ?
>
> The dhcp relay is version 4.3.6 self compiled and running inside a docker
> container.
>
> Routing is enabled between the IU and ID interfaces
>
>
>
> Start command dhcrelay -4 -d -iu ens18 -id br_TB102_TMN 10.160.5.2
>
> # route
>
> Kernel IP routing table
>
> Destination Gateway Genmask Flags Metric Ref Use
> Iface
>
> default gateway 0.0.0.0 UG 0 0 0
> ens18
>
> 10.160.8.0 0.0.0.0 255.255.254.0 U 0 0 0
> ens18
>
> 10.160.50.16 0.0.0.0 255.255.255.240 U 0 0 0
> br_TB102_TMN
>
> 172.17.0.0 0.0.0.0 255.255.0.0 U 0 0 0
> docker0
>
> #brctl show
>
> # brctl show
>
> bridge name bridge id STP enabled
> interfaces
>
> br_TB102_DPU 8000.42b99b1e1cc9
> no ens19.2002
>
>
> ens19.2002.4090
>
> br_TB102_TMN 8000.7a598845a623
> no ens20.1002
>
> docker0 8000.0242380e275a
> no
>
>
>
> #ip a
>
> ip a
>
> 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group
> default qlen 1000
>
> link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
>
> inet 127.0.0.1/8 scope host lo
>
> valid_lft forever preferred_lft forever
>
> inet6 ::1/128 scope host
>
> valid_lft forever preferred_lft forever
>
> 2: ens18: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
> state UP group default qlen 1000
>
> link/ether 36:78:14:96:53:13 brd ff:ff:ff:ff:ff:ff
>
> inet 10.160.8.83/23 brd 10.160.9.255 scope global ens18
>
> valid_lft forever preferred_lft forever
>
> inet6 fe80::3478:14ff:fe96:5313/64 scope link
>
> valid_lft forever preferred_lft forever
>
> 3: ens19: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
> state UP group default qlen 1000
>
> link/ether 42:b9:9b:1e:1c:c9 brd ff:ff:ff:ff:ff:ff
>
> inet6 fe80::40b9:9bff:fe1e:1cc9/64 scope link
>
> valid_lft forever preferred_lft forever
>
> 4: ens20: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
> state UP group default qlen 1000
>
> link/ether 7a:59:88:45:a6:23 brd ff:ff:ff:ff:ff:ff
>
> inet6 fe80::7859:88ff:fe45:a623/64 scope link
>
> valid_lft forever preferred_lft forever
>
> 5: ens20.1002 at ens20: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc
> noqueue master br_TB102_TMN state UP group default qlen 1000
>
> link/ether 7a:59:88:45:a6:23 brd ff:ff:ff:ff:ff:ff
>
> inet6 fe80::7859:88ff:fe45:a623/64 scope link
>
> valid_lft forever preferred_lft forever
>
> 6: ens19.2002 at ens19: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc
> noqueue master br_TB102_DPU state UP group default qlen 1000
>
> link/ether 42:b9:9b:1e:1c:c9 brd ff:ff:ff:ff:ff:ff
>
> inet6 fe80::40b9:9bff:fe1e:1cc9/64 scope link
>
> valid_lft forever preferred_lft forever
>
> 7: br_TB102_DPU: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue
> state UP group default qlen 1000
>
> link/ether 42:b9:9b:1e:1c:c9 brd ff:ff:ff:ff:ff:ff
>
> inet 10.160.60.17/28 brd 10.160.60.31 scope global br_TB102_DPU
>
> valid_lft forever preferred_lft forever
>
> inet6 fe80::40b9:9bff:fe1e:1cc9/64 scope link
>
> valid_lft forever preferred_lft forever
>
> 8: br_TB102_TMN: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue
> state UP group default qlen 1000
>
> link/ether 7a:59:88:45:a6:23 brd ff:ff:ff:ff:ff:ff
>
> inet 10.160.50.17/28 brd 10.160.50.31 scope global br_TB102_TMN
>
> valid_lft forever preferred_lft forever
>
> inet6 fe80::7859:88ff:fe45:a623/64 scope link
>
> valid_lft forever preferred_lft forever
>
> 9: ens19.2002.4090 at ens19.2002: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500
> qdisc noqueue master br_TB102_DPU state UP group default qlen 1000
>
> link/ether 42:b9:9b:1e:1c:c9 brd ff:ff:ff:ff:ff:ff
>
> inet6 fe80::40b9:9bff:fe1e:1cc9/64 scope link
>
> valid_lft forever preferred_lft forever
>
> 10: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue
> state DOWN group default
>
> link/ether 02:42:38:0e:27:5a brd ff:ff:ff:ff:ff:ff
>
> inet 172.17.0.1/16 scope global docker0
>
> valid_lft forever preferred_lft forever
>
> inet6 fe80::42:38ff:fe0e:275a/64 scope link
>
> valid_lft forever preferred_lft forever
>
>
>
> pcap is available at:
>
> https://turl.ca/semr
>
>
>
> Mit freundlichen Grüßen / With kind regards
>
>
>
> Immo Wetzel
>
>
>
> ADTRAN GmbH
>
> Siemensallee 1
>
> 17489 Greifswald
>
> Germany
>
>
>
> Phone: +49 3834 5352 823 <+49%203834%205352823>
>
> Mobile: +49 151 147 29 225 <+49%201511%204729225>
>
> Skype: immo_wetzel_adtran
>
> Immo.Wetzel at Adtran.com PGP-Fingerprint: 7313 7E88 4E19 AACF 45E9 E74D
> EFF7 0480 F4CF 6426
>
> http://www.adtran.com
>
>
>
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>
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>
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>
> This message has been classified *General Business* by * IMMO WETZEL* on
> Montag, 15. Januar 2018 at 16:19:17.
>
>
>
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