dhcrelay duplicated request

IMMO WETZEL IMMO.WETZEL at adtran.com
Mon Jan 15 15:21:05 UTC 2018


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
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Skype: immo_wetzel_adtran
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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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