DHCP issue with Win 10 clients

karnauskas · August 28, 2020, 10:57am

I’m having issues with DHCP server and Windows 10 clients. DHCP server is serving basic things, like IP, Gateway and DNS addresses. Mac OS X / phones works without problem. Windows 10 is not getting anything from DHCP server. From debug logs it looks like DHCP server is receiving request from Windows 10 machine but not giving any response. This issue is with v6.47.2 and few previous stable releases. Anyone else having similar issues?

biomesh · August 28, 2020, 11:02am

Sounds like a config issue as it works partially. Please post your config so we can see how it is configured.

karnauskas · August 28, 2020, 11:33am

Config fragments

/ip address
add address=10.0.0.254/24 disabled=no interface=br_lan network=10.0.0.0

/ip pool
add name=pool1 ranges=10.0.0.30-10.0.0.100

/ip dhcp-server config
set accounting=yes interim-update=0s store-leases-disk=5m

/ip dhcp-server network
add address=10.0.0.0/24 caps-manager="" dhcp-option="" dns-server=10.0.0.254 \
    gateway=10.0.0.254 ntp-server=10.0.0.254 wins-server=""

/ip dhcp-server
add add-arp=yes address-pool=pool1 delay-threshold=5m disabled=no interface=\
    br_lan lease-script="" lease-time=10m name=server1 use-radius=no

Logs for Windows 10 device, no response

12:18:24 dhcp,debug,packet server1 received discover with id 2822046763 from 0.0.0.0
12:18:24 dhcp,debug,packet     secs = 7168
12:18:24 dhcp,debug,packet     ciaddr = 0.0.0.0
12:18:24 dhcp,debug,packet     chaddr = xx:yy:zz:aa:bb:cc
12:18:24 dhcp,debug,packet     Msg-Type = discover
12:18:24 dhcp,debug,packet     Client-Id = 01-D4-D2-52-40-0B-EE
12:18:24 dhcp,debug,packet     Host-Name = "DESKTOP-TEST"
12:18:24 dhcp,debug,packet     Class-Id = "MSFT 5.0"
12:18:24 dhcp,debug,packet     Parameter-List = Subnet-Mask,Router,Domain-Server,Domain-Name,Router-Discovery,Static-Route,Vendor-Specific,NETBIOS-Name-Server,NETBIOS-Node-Type,NETBIOS-Scope,Domain-Search,Classless-Route,MS-Classless-Route,Auto-Proxy-Config

Logs for Raspberry pi running aarm64 (same result with/without static IP allocation)

12:20:13 dhcp,debug,packet server1 received request with id 2913399079 from 10.0.0.4
12:20:13 dhcp,debug,packet     secs = 2102
12:20:13 dhcp,debug,packet     ciaddr = 10.0.0.4
12:20:13 dhcp,debug,packet     chaddr = xx:yy:zz:aa:bb:dd
12:20:13 dhcp,debug,packet     Msg-Type = request
12:20:13 dhcp,debug,packet     Client-Id = FF-5D-1D-B6-2E-00-02-00-00-AB-11-D1-51-29-40-1A-4E-F3-EC
12:20:13 dhcp,debug,packet     Parameter-List = Subnet-Mask,Router,Host-Name,Domain-Name,Domain-Server,Interface-MTU,Static-Route,Classless-Route,Domain-Search,NTP-Server,Unknown(120)
12:20:13 dhcp,debug,packet     Max-DHCP-Message-Size = 576
12:20:13 dhcp,debug,packet     Client-FQDN = 05-00-00-06-72-70-69-34-2D-32-04-6E-6B-74-73-02-6C-74-00
12:20:13 dhcp,debug,packet server1 sending ack with id 2913399079 to 10.0.0.4
12:20:13 dhcp,debug,packet     ciaddr = 10.0.0.4
12:20:13 dhcp,debug,packet     yiaddr = 10.0.0.4
12:20:13 dhcp,debug,packet     siaddr = 10.0.0.254
12:20:13 dhcp,debug,packet     chaddr = xx:yy:zz:aa:bb:dd
12:20:13 dhcp,debug,packet     Msg-Type = ack
12:20:13 dhcp,debug,packet     Server-Id = 10.0.0.254
12:20:13 dhcp,debug,packet     Address-Time = 600
12:20:13 dhcp,debug,packet     Subnet-Mask = 255.255.255.0
12:20:13 dhcp,debug,packet     Router = 10.0.0.254
12:20:13 dhcp,debug,packet     Domain-Server = 10.0.0.254
12:20:13 dhcp,debug,packet     NTP-Server = 10.0.0.254

biomesh · August 28, 2020, 12:54pm

Update your dhcp server from

/ip dhcp-server
add add-arp=yes address-pool=pool1 delay-threshold=5m disabled=no interface=
br_lan lease-script=“” lease-time=10m name=server1 use-radius=no

to

/ip dhcp-server
add add-arp=yes address-pool=pool1 authoritative=yes disabled=no interface=
br_lan lease-script=“” lease-time=10m name=server1 use-radius=no

I removed the delay-threshold (which I am sure is your real issue) and also set authoritative=yes.

karnauskas · August 28, 2020, 3:56pm

Thanks @biomesh, you were right about delay-threshold, I removed this and things seems behaving normally. I was not paying attention to secs bit. But now after looking at it (supposed to be seconds from dhcp client start), for some reason Windows multiplies this value by *256. Why? Is this known bug? Sadly can’t check mikrotik’s source code nor microsoft’s dhcp client. Is dhcp server ignoring packets with without secs header if delay-threshold is set?

But this is nuts, not following rfc

16:40:07 dhcp,debug,packet server1 received discover with id 1229905021 from 0.0.0.0
16:40:07 dhcp,debug,packet     flags = broadcast
16:40:07 dhcp,debug,packet     ciaddr = 0.0.0.0
16:40:07 dhcp,debug,packet     chaddr = AA:BB:CC:DD:EE:FF
16:40:07 dhcp,debug,packet     Msg-Type = discover
16:40:07 dhcp,debug,packet     Client-Id = 01-AA-BB-CC-DD-EE-FF
16:40:07 dhcp,debug,packet     Address-Request = 10.0.0.98
16:40:07 dhcp,debug,packet     Host-Name = "DESKTOP-TEST"
16:40:07 dhcp,debug,packet     Class-Id = "MSFT 5.0"
16:40:07 dhcp,debug,packet     Parameter-List = Subnet-Mask,Router,Domain-Server,Domain-Name,Router-Discovery,Static-Route,Vendor-Specific,NETBIOS-Name-Server,NETBIOS-Node-Type,NETBIOS-Scope,Domain-Search,Classless-Route,MS-Classless-Route,Auto-Proxy-Config
16:40:10 dhcp,debug,packet server1 received discover with id 1229905021 from 0.0.0.0
16:40:10 dhcp,debug,packet     secs = 768
16:40:10 dhcp,debug,packet     flags = broadcast
16:40:10 dhcp,debug,packet     ciaddr = 0.0.0.0
16:40:10 dhcp,debug,packet     chaddr = AA:BB:CC:DD:EE:FF
16:40:10 dhcp,debug,packet     Msg-Type = discover
16:40:10 dhcp,debug,packet     Client-Id = 01-AA-BB-CC-DD-EE-FF
16:40:10 dhcp,debug,packet     Address-Request = 10.0.0.98
16:40:10 dhcp,debug,packet     Host-Name = "DESKTOP-TEST"
16:40:10 dhcp,debug,packet     Class-Id = "MSFT 5.0"
16:40:10 dhcp,debug,packet     Parameter-List = Subnet-Mask,Router,Domain-Server,Domain-Name,Router-Discovery,Static-Route,Vendor-Specific,NETBIOS-Name-Server,NETBIOS-Node-Type,NETBIOS-Scope,Domain-Search,Classless-Route,MS-Classless-Route,Auto-Proxy-Config
16:40:19 dhcp,debug,packet server1 received discover with id 1229905021 from 0.0.0.0
16:40:19 dhcp,debug,packet     secs = 3072
16:40:19 dhcp,debug,packet     flags = broadcast
16:40:19 dhcp,debug,packet     ciaddr = 0.0.0.0
16:40:19 dhcp,debug,packet     chaddr = AA:BB:CC:DD:EE:FF
16:40:19 dhcp,debug,packet     Msg-Type = discover
16:40:19 dhcp,debug,packet     Client-Id = 01-AA-BB-CC-DD-EE-FF
16:40:19 dhcp,debug,packet     Address-Request = 10.0.0.98
16:40:19 dhcp,debug,packet     Host-Name = "DESKTOP-TEST"
16:40:19 dhcp,debug,packet     Class-Id = "MSFT 5.0"
16:40:19 dhcp,debug,packet     Parameter-List = Subnet-Mask,Router,Domain-Server,Domain-Name,Router-Discovery,Static-Route,Vendor-Specific,NETBIOS-Name-Server,NETBIOS-Node-Type,NETBIOS-Scope,Domain-Search,Classless-Route,MS-Classless-Route,Auto-Proxy-Config
16:40:34 dhcp,debug,packet server1 received discover with id 1229905021 from 0.0.0.0
16:40:34 dhcp,debug,packet     secs = 6912
16:40:34 dhcp,debug,packet     flags = broadcast
16:40:34 dhcp,debug,packet     ciaddr = 0.0.0.0
16:40:34 dhcp,debug,packet     chaddr = AA:BB:CC:DD:EE:FF
16:40:34 dhcp,debug,packet     Msg-Type = discover
16:40:34 dhcp,debug,packet     Client-Id = 01-AA-BB-CC-DD-EE-FF
16:40:34 dhcp,debug,packet     Address-Request = 10.0.0.98
16:40:34 dhcp,debug,packet     Host-Name = "DESKTOP-TEST"
16:40:34 dhcp,debug,packet     Class-Id = "MSFT 5.0"
16:40:34 dhcp,debug,packet     Parameter-List = Subnet-Mask,Router,Domain-Server,Domain-Name,Router-Discovery,Static-Route,Vendor-Specific,NETBIOS-Name-Server,NETBIOS-Node-Type,NETBIOS-Scope,Domain-Search,Classless-Route,MS-Classless-Route,Auto-Proxy-Config