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Unifi AP is unable to complete DHCP with EX2200 Switch Windows Server 2016 DHCP

‎09-03-2020 09:57 PM

I'm trying to get my Unifi AP on my network but I'm having a tough time getting DHCP to work with it. I have my DHCP server working on a different subnet. I have bootp helpers configured with dhcp-relay-agent along with my DHCP server for all of my VLANs on this switch. I noticed after doing a pcap that my AP is receiving a DHCP offer message but then going into an ARP loop where it requests the gateway, receives a response but then continually requests the MAC of the gateway. Is there something else I need to configure to get this to work? Packet Capture and sanitized config is below.

 

PCAP:

14:01:24.258194 Out IP 0.0.0.0 > 224.0.0.1: igmp query v2
14:01:24.260177 Out IP 0.0.0.0 > 224.0.0.1: igmp query v2
14:01:24.940126 Out STP 802.1w, Rapid STP, Flags [Proposal], bridge-id 8000.5c:5e:ab:70:e1:01.822d, length 36
14:01:26.259176 Out IP 0.0.0.0 > 224.0.0.1: igmp query v2
14:01:26.260903 Out IP 0.0.0.0 > 224.0.0.1: igmp query v2
14:01:26.879076 Out STP 802.1w, Rapid STP, Flags [Proposal], bridge-id 8000.5c:5e:ab:70:e1:01.822d, length 36
14:01:27.125544 In IP6 fe80::822a:a8ff:fe19:995b > ff02::2: ICMP6, router solicitation , length 16
14:01:28.847581 Out STP 802.1w, Rapid STP, Flags [Proposal], bridge-id 8000.5c:5e:ab:70:e1:01.822d, length 36
14:01:30.743371 Out STP 802.1w, Rapid STP, Flags [Proposal], bridge-id 8000.5c:5e:ab:70:e1:01.822d, length 36
14:01:31.134914 In IP6 fe80::822a:a8ff:fe19:995b > ff02::2: ICMP6, router solicitation , length 16
14:01:32.572936 Out STP 802.1w, Rapid STP, Flags [Proposal], bridge-id 8000.5c:5e:ab:70:e1:01.822d, length 36
14:01:34.448114 Out STP 802.1w, Rapid STP, Flags [Proposal], bridge-id 8000.5c:5e:ab:70:e1:01.822d, length 36
14:01:36.350146 Out STP 802.1w, Rapid STP, Flags [Proposal], bridge-id 8000.5c:5e:ab:70:e1:01.822d, length 36
14:01:36.735177 In IP truncated-ip - 321 bytes missing! 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request [|bootp]
14:01:36.757313 Out IP truncated-ip - 292 bytes missing! 10.4.51.1.bootps > 10.4.51.3.bootpc: BOOTP/DHCP, Reply, length 320
14:01:36.760229 In IP truncated-ip - 333 bytes missing! 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request [|bootp]
14:01:36.778264 Out IP truncated-ip - 292 bytes missing! 10.4.51.1.bootps > 10.4.51.3.bootpc: BOOTP/DHCP, Reply, length 320
14:01:36.890499 In arp who-has 10.4.51.1 tell 10.4.51.3
14:01:36.890852 Out arp reply 10.4.51.1 is-at 5c:5e:ab:70:e1:01
14:01:36.950167 In arp who-has 10.4.51.1 (Broadcast) tell 10.4.51.3
14:01:36.950485 Out arp reply 10.4.51.1 is-at 5c:5e:ab:70:e1:01
14:01:37.885160 In arp who-has 10.4.51.1 tell 10.4.51.3
14:01:37.885480 Out arp reply 10.4.51.1 is-at 5c:5e:ab:70:e1:01
14:01:37.956955 In arp who-has 10.4.51.1 (Broadcast) tell 10.4.51.3
14:01:37.957273 Out arp reply 10.4.51.1 is-at 5c:5e:ab:70:e1:01
14:01:38.334141 Out STP 802.1w, Rapid STP, Flags [Proposal], bridge-id 8000.5c:5e:ab:70:e1:01.822d, length 36
14:01:38.885160 In arp who-has 10.4.51.1 tell 10.4.51.3
14:01:38.885479 Out arp reply 10.4.51.1 is-at 5c:5e:ab:70:e1:01
14:01:39.086180 In arp who-has 10.4.51.1 (Broadcast) tell 10.4.51.3
14:01:39.086494 Out arp reply 10.4.51.1 is-at 5c:5e:ab:70:e1:01
14:01:40.094871 In arp who-has 10.4.51.1 (Broadcast) tell 10.4.51.3
14:01:40.095189 Out arp reply 10.4.51.1 is-at 5c:5e:ab:70:e1:01
14:01:40.154973 Out STP 802.1w, Rapid STP, Flags [Proposal], bridge-id 8000.5c:5e:ab:70:e1:01.822d, length 36
14:01:41.895235 In arp who-has 10.4.51.1 tell 10.4.51.3
14:01:41.895549 Out arp reply 10.4.51.1 is-at 5c:5e:ab:70:e1:01
14:01:42.143391 Out STP 802.1w, Rapid STP, Flags [Proposal], bridge-id 8000.5c:5e:ab:70:e1:01.822d, length 36
14:01:42.895251 In arp who-has 10.4.51.1 tell 10.4.51.3
14:01:42.895565 Out arp reply 10.4.51.1 is-at 5c:5e:ab:70:e1:01
14:01:43.895267 In arp who-has 10.4.51.1 tell 10.4.51.3
14:01:43.895579 Out arp reply 10.4.51.1 is-at 5c:5e:ab:70:e1:01
14:01:43.950828 Out STP 802.1w, Rapid STP, Flags [Proposal], bridge-id 8000.5c:5e:ab:70:e1:01.822d, length 36
14:01:45.758998 Out STP 802.1w, Rapid STP, Flags [Proposal], bridge-id 8000.5c:5e:ab:70:e1:01.822d, length 36
14:01:46.901051 In arp who-has 10.4.51.1 tell 10.4.51.3
14:01:46.901367 Out arp reply 10.4.51.1 is-at 5c:5e:ab:70:e1:01
14:01:47.708213 Out STP 802.1w, Rapid STP, Flags [Proposal], bridge-id 8000.5c:5e:ab:70:e1:01.822d, length 36
14:01:47.895276 In arp who-has 10.4.51.1 tell 10.4.51.3
14:01:47.895590 Out arp reply 10.4.51.1 is-at 5c:5e:ab:70:e1:01
14:01:48.896285 In arp who-has 10.4.51.1 tell 10.4.51.3
14:01:48.896597 Out arp reply 10.4.51.1 is-at 5c:5e:ab:70:e1:01
14:01:49.645686 Out STP 802.1w, Rapid STP, Flags [Proposal], bridge-id 8000.5c:5e:ab:70:e1:01.822d, length 36

 

 

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Ethernet Switching

Re: Unifi AP is unable to complete DHCP with EX2200 Switch Windows Server 2016 DHCP

‎09-04-2020 06:07 AM

In order to determine if a DORA packet is getting stucked in the juniper device please monitor the ingress and egress interfaces using monitor traffic interface <interface name> size 1500 no resolve matching "port 67||68"

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