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I'm trying to use a Phytron MCC-1 motor controller which gets its IP only via DHCP (no manual setting). I setup isc-dhcp-server on ubuntu as such:

# /etc/dhcp/dhcpd.conf
option domain-name "example.org";
option domain-name-servers ns1.example.org, ns2.example.org;

default-lease-time 600;
max-lease-time 7200;

ddns-update-style none;

subnet 192.168.0.0 netmask 255.255.255.0 {
        default-lease-time 21600;
        option subnet-mask 255.255.255.0;
}

host phytronmcc1 {
        hardware ethernet 00:50:c2:b2:11:75;
        fixed-address 192.168.0.30;
        option host-name "phytronmmc1";
}

I want to use the dhcp server on enxd8eb97b9a6d4:

$ ifconfig
enp0s25: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 134.158.40.174  netmask 255.255.248.0  broadcast 134.158.47.255
        inet6 fe80::193c:fd36:6263:9faf  prefixlen 64  scopeid 0x20<link>
        ether 70:5a:0f:ee:1e:80  txqueuelen 1000  (Ethernet)
        RX packets 129829774  bytes 87461213325 (87.4 GB)
        RX errors 0  dropped 435  overruns 0  frame 0
        TX packets 34660884  bytes 3579056486 (3.5 GB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
        device interrupt 20  memory 0xd2200000-d2220000  

enxd8eb97b9a6d4: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.0.31  netmask 255.255.255.0  broadcast 192.168.0.255
        ether d8:eb:97:b9:a6:d4  txqueuelen 1000  (Ethernet)
        RX packets 2563  bytes 117898 (117.8 KB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 4950  bytes 1034703 (1.0 MB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 1905619  bytes 23318260587 (23.3 GB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 1905619  bytes 23318260587 (23.3 GB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

wlp62s0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        ether fa:5e:ff:b8:4a:22  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

Now the syslog seems fine, except I don't see the device:

# /var/log/syslog
dhcpd[22892]: Internet Systems Consortium DHCP Server 4.3.5
dhcpd[22892]: Copyright 2004-2016 Internet Systems Consortium.
sh[22892]: For info, please visit https://www.isc.org/software/dhcp/
dhcpd[22892]: All rights reserved.
dhcpd[22892]: For info, please visit https://www.isc.org/software/dhcp/
dhcpd[22892]: Config file: /etc/dhcp/dhcpd.conf
sh[22892]: Config file: /etc/dhcp/dhcpd.conf
sh[22892]: Database file: /var/lib/dhcp/dhcpd.leases
sh[22892]: PID file: /run/dhcp-server/dhcpd.pid
dhcpd[22892]: Database file: /var/lib/dhcp/dhcpd.leases
dhcpd[22892]: PID file: /run/dhcp-server/dhcpd.pid
dhcpd[22892]: Wrote 0 deleted host decls to leases file.
dhcpd[22892]: Wrote 0 new dynamic host decls to leases file.
dhcpd[22892]: Wrote 0 leases to leases file.
dhcpd[22892]: Listening on LPF/enxd8eb97b9a6d4/d8:eb:97:b9:a6:d4/192.168.0.0/24
dhcpd[22892]: Sending on   LPF/enxd8eb97b9a6d4/d8:eb:97:b9:a6:d4/192.168.0.0/24
sh[22892]:    in your dhcpd.conf file for the network segment
sh[22892]:    in your dhcpd.conf file for the network segment
dhcpd[22892]: 
dhcpd[22892]: No subnet declaration for wlp62s0 (no IPv4 addresses).
dhcpd[22892]: ** Ignoring requests on wlp62s0.  If this is not what
dhcpd[22892]:    you want, please write a subnet declaration
dhcpd[22892]:    in your dhcpd.conf file for the network segment
dhcpd[22892]:    to which interface wlp62s0 is attached. **
dhcpd[22892]: 
dhcpd[22892]: 
dhcpd[22892]: No subnet declaration for enp0s25 (134.158.40.174).
dhcpd[22892]: ** Ignoring requests on enp0s25.  If this is not what
dhcpd[22892]:    you want, please write a subnet declaration
dhcpd[22892]:    in your dhcpd.conf file for the network segment
dhcpd[22892]:    to which interface enp0s25 is attached. **
dhcpd[22892]: 
dhcpd[22892]: Sending on   Socket/fallback/fallback-net
dhcpd[22892]: Server starting service.

Using wireshark only shows 2 frames:

Frame 7219: 188 bytes on wire (1504 bits), 188 bytes captured (1504 bits) on interface 0
Ethernet II, Src: Trendnet_b9:a6:d4 (d8:eb:97:b9:a6:d4), Dst: Broadcast (ff:ff:ff:ff:ff:ff)
    Destination: Broadcast (ff:ff:ff:ff:ff:ff)
    Source: Trendnet_b9:a6:d4 (d8:eb:97:b9:a6:d4)
    Type: IPv4 (0x0800)
Internet Protocol Version 4, Src: 192.168.0.31, Dst: 192.168.0.255
User Datagram Protocol, Src Port: 17500, Dst Port: 17500
Dropbox LAN sync Discovery Protocol

Frame 7138: 60 bytes on wire (480 bits), 60 bytes captured (480 bits) on interface 0
Ethernet II, Src: Phytron-_01:75 (00:50:c2:b2:11:75), Dst: LLDP_Multicast (01:80:c2:00:00:0e)
    Destination: LLDP_Multicast (01:80:c2:00:00:0e)
    Source: Phytron-_01:75 (00:50:c2:b2:11:75)
    Type: 802.1 Link Layer Discovery Protocol (LLDP) (0x88cc)
Link Layer Discovery Protocol
    Chassis Subtype = Network address, Id: 0.0.0.0
        0000 001. .... .... = TLV Type: Chassis Id (1)
        .... ...0 0000 0110 = TLV Length: 6
        Chassis Id Subtype: Network address (5)
        Network Address family: IPv4 (1)
        Chassis Id: 0.0.0.0
    Port Subtype = MAC address, Id: 00:50:c2:b2:11:75
        0000 010. .... .... = TLV Type: Port Id (2)
        .... ...0 0000 0111 = TLV Length: 7
        Port Id Subtype: MAC address (3)
        Port Id: Phytron-_01:75 (00:50:c2:b2:11:75)
    Time To Live = 120 sec
    System Description = MCCe
        0000 110. .... .... = TLV Type: System Description (6)
        .... ...0 0000 0100 = TLV Length: 4
        System Description: MCCe
    End of LLDPDU

So, obviously the device is there but doesn't get an IP. Is it my DHCP configuration ? Something else ? Anything I can try ?

dargaud
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    Your Phytron device is not requesting an IP address via DHCP. You should start by looking at the device. – Michael Hampton Feb 13 '19 at 14:41
  • Yes. The reset button wasn't relaunching the DHCP request. Power unplug/replug did, and now it gets the IP address. Thanks – dargaud Feb 13 '19 at 15:40

0 Answers0