[root@dhcp-server ~]# tcpdump -i ens224 'port 67 or port 68' -vvv tcpdump: listening on ens224, link-type EN10MB (Ethernet), capture size 65535 bytes 11:18:19.830492 IP (tos 0x10, ttl 254, id 29216, offset 0, flags [none], proto UDP (17), length 374) 22.22.22.21.bootps > dhcp-server.localdomain.bootps: [udp sum ok] BOOTP/DHCP, Request from 00:25:b5:00:00:01 (oui Unknown), length 346, hops 1, xid 0xf0c7735e, Flags [none] (0x0000) Gateway-IP 22.22.22.21 Client-Ethernet-Address 00:25:b5:00:00:01 (oui Unknown) Vendor-rfc1048 Extensions Magic Cookie 0x63825363 DHCP-Message Option 53, length 1: Discover Parameter-Request Option 55, length 18: Subnet-Mask, BR, Time-Zone, Classless-Static-Route Domain-Name, Domain-Name-Server, Hostname, YD YS, NTP, MTU, Option 119 Default-Gateway, Classless-Static-Route, Classless-Static-Route-Microsoft, Static-Route Option 252, NTP Agent-Information Option 82, length 44: Circuit-ID SubOption 1, length 10: ^A^H^@^F^@LO*^@^I Remote-ID SubOption 2, length 6: M-LFM-V!M-)w Unknown SubOption 151, length 10: 0x0000: 0062 6274 2d76 786c 616e Unknown SubOption 11, length 4: 0x0000: 0aa8 6601 Unknown SubOption 5, length 4: 0x0000: 0aa8 6600 END Option 255, length 0 PAD Option 0, length 0, occurs 36 11:18:22.087323 IP (tos 0xc0, ttl 64, id 20920, offset 0, flags [none], proto UDP (17), length 372) dhcp-server.localdomain.bootps > 22.22.22.21.bootps: [bad udp cksum 0x9d58 -> 0xbe56!] BOOTP/DHCP, Reply, length 344, hops 1, xid 0xf0c7735e, Flags [none] (0x0000) Your-IP 10.168.102.132 Server-IP dhcp-server.localdomain Gateway-IP 22.22.22.21 Client-Ethernet-Address 00:25:b5:00:00:01 (oui Unknown) Vendor-rfc1048 Extensions Magic Cookie 0x63825363 DHCP-Message Option 53, length 1: Offer Server-ID Option 54, length 4: 10.168.102.1 Lease-Time Option 51, length 4: 43200 RN Option 58, length 4: 21600 RB Option 59, length 4: 37800 SUBNET Option 118, length 4: 10.168.102.0 Subnet-Mask Option 1, length 4: 255.255.255.0 BR Option 28, length 4: 10.168.102.255 Domain-Name-Server Option 6, length 4: dhcp-server.localdomain Default-Gateway Option 3, length 4: 10.168.102.1 Agent-Information Option 82, length 44: Circuit-ID SubOption 1, length 10: ^A^H^@^F^@LO*^@^I Remote-ID SubOption 2, length 6: M-LFM-V!M-)w Unknown SubOption 151, length 10: 0x0000: 0062 6274 2d76 786c 616e Unknown SubOption 11, length 4: 0x0000: 0aa8 6601 Unknown SubOption 5, length 4: 0x0000: 0aa8 6600 END Option 255, length 0 11:18:22.088871 IP (tos 0x10, ttl 254, id 29219, offset 0, flags [none], proto UDP (17), length 374) 22.22.22.21.bootps > dhcp-server.localdomain.bootps: [udp sum ok] BOOTP/DHCP, Request from 00:25:b5:00:00:01 (oui Unknown), length 346, hops 1, xid 0xf0c7735e, Flags [none] (0x0000) Gateway-IP 22.22.22.21 Client-Ethernet-Address 00:25:b5:00:00:01 (oui Unknown) Vendor-rfc1048 Extensions Magic Cookie 0x63825363 DHCP-Message Option 53, length 1: Request Server-ID Option 54, length 4: dhcp-server.localdomain Requested-IP Option 50, length 4: 10.168.102.132 Parameter-Request Option 55, length 18: Subnet-Mask, BR, Time-Zone, Classless-Static-Route Domain-Name, Domain-Name-Server, Hostname, YD YS, NTP, MTU, Option 119 Default-Gateway, Classless-Static-Route, Classless-Static-Route-Microsoft, Static-Route Option 252, NTP Agent-Information Option 82, length 44: Circuit-ID SubOption 1, length 10: ^A^H^@^F^@LO*^@^I Remote-ID SubOption 2, length 6: M-LFM-V!M-)w Unknown SubOption 151, length 10: 0x0000: 0062 6274 2d76 786c 616e Unknown SubOption 11, length 4: 0x0000: 0aa8 6601 Unknown SubOption 5, length 4: 0x0000: 0aa8 6600 END Option 255, length 0 PAD Option 0, length 0, occurs 24 11:18:24.825335 IP (tos 0x10, ttl 254, id 29223, offset 0, flags [none], proto UDP (17), length 374) 22.22.22.21.bootps > dhcp-server.localdomain.bootps: [udp sum ok] BOOTP/DHCP, Request from 00:25:b5:00:00:01 (oui Unknown), length 346, hops 1, xid 0xf0c7735e, Flags [none] (0x0000) Gateway-IP 22.22.22.21 Client-Ethernet-Address 00:25:b5:00:00:01 (oui Unknown) Vendor-rfc1048 Extensions Magic Cookie 0x63825363 DHCP-Message Option 53, length 1: Request Server-ID Option 54, length 4: dhcp-server.localdomain Requested-IP Option 50, length 4: 10.168.102.132 Parameter-Request Option 55, length 18: Subnet-Mask, BR, Time-Zone, Classless-Static-Route Domain-Name, Domain-Name-Server, Hostname, YD YS, NTP, MTU, Option 119 Default-Gateway, Classless-Static-Route, Classless-Static-Route-Microsoft, Static-Route Option 252, NTP Agent-Information Option 82, length 44: Circuit-ID SubOption 1, length 10: ^A^H^@^F^@LO*^@^I Remote-ID SubOption 2, length 6: M-LFM-V!M-)w Unknown SubOption 151, length 10: 0x0000: 0062 6274 2d76 786c 616e Unknown SubOption 11, length 4: 0x0000: 0aa8 6601 Unknown SubOption 5, length 4: 0x0000: 0aa8 6600 END Option 255, length 0 PAD Option 0, length 0, occurs 24 11:18:30.703779 IP (tos 0x10, ttl 254, id 29230, offset 0, flags [none], proto UDP (17), length 374) 22.22.22.21.bootps > dhcp-server.localdomain.bootps: [udp sum ok] BOOTP/DHCP, Request from 00:25:b5:00:00:01 (oui Unknown), length 346, hops 1, xid 0xf0c7735e, Flags [none] (0x0000) Gateway-IP 22.22.22.21 Client-Ethernet-Address 00:25:b5:00:00:01 (oui Unknown) Vendor-rfc1048 Extensions Magic Cookie 0x63825363 DHCP-Message Option 53, length 1: Request Server-ID Option 54, length 4: dhcp-server.localdomain Requested-IP Option 50, length 4: 10.168.102.132 Parameter-Request Option 55, length 18: Subnet-Mask, BR, Time-Zone, Classless-Static-Route Domain-Name, Domain-Name-Server, Hostname, YD YS, NTP, MTU, Option 119 Default-Gateway, Classless-Static-Route, Classless-Static-Route-Microsoft, Static-Route Option 252, NTP Agent-Information Option 82, length 44: Circuit-ID SubOption 1, length 10: ^A^H^@^F^@LO*^@^I Remote-ID SubOption 2, length 6: M-LFM-V!M-)w Unknown SubOption 151, length 10: 0x0000: 0062 6274 2d76 786c 616e Unknown SubOption 11, length 4: 0x0000: 0aa8 6601 Unknown SubOption 5, length 4: 0x0000: 0aa8 6600 END Option 255, length 0 PAD Option 0, length 0, occurs 24 11:18:37.337487 IP (tos 0x10, ttl 254, id 29238, offset 0, flags [none], proto UDP (17), length 374) 22.22.22.21.bootps > dhcp-server.localdomain.bootps: [udp sum ok] BOOTP/DHCP, Request from 00:25:b5:00:00:01 (oui Unknown), length 346, hops 1, xid 0xd2c3606e, Flags [none] (0x0000) Gateway-IP 22.22.22.21 Client-Ethernet-Address 00:25:b5:00:00:01 (oui Unknown) Vendor-rfc1048 Extensions Magic Cookie 0x63825363 DHCP-Message Option 53, length 1: Discover Parameter-Request Option 55, length 18: Subnet-Mask, BR, Time-Zone, Classless-Static-Route Domain-Name, Domain-Name-Server, Hostname, YD YS, NTP, MTU, Option 119 Default-Gateway, Classless-Static-Route, Classless-Static-Route-Microsoft, Static-Route Option 252, NTP Agent-Information Option 82, length 44: Circuit-ID SubOption 1, length 10: ^A^H^@^F^@LO*^@^I Remote-ID SubOption 2, length 6: M-LFM-V!M-)w Unknown SubOption 151, length 10: 0x0000: 0062 6274 2d76 786c 616e Unknown SubOption 11, length 4: 0x0000: 0aa8 6601 Unknown SubOption 5, length 4: 0x0000: 0aa8 6600 END Option 255, length 0 PAD Option 0, length 0, occurs 36 11:18:37.337917 IP (tos 0xc0, ttl 64, id 21946, offset 0, flags [none], proto UDP (17), length 372) dhcp-server.localdomain.bootps > 22.22.22.21.bootps: [bad udp cksum 0x9d58 -> 0xef4a!] BOOTP/DHCP, Reply, length 344, hops 1, xid 0xd2c3606e, Flags [none] (0x0000) Your-IP 10.168.102.132 Server-IP dhcp-server.localdomain Gateway-IP 22.22.22.21 Client-Ethernet-Address 00:25:b5:00:00:01 (oui Unknown) Vendor-rfc1048 Extensions Magic Cookie 0x63825363 DHCP-Message Option 53, length 1: Offer Server-ID Option 54, length 4: 10.168.102.1 Lease-Time Option 51, length 4: 43200 RN Option 58, length 4: 21600 RB Option 59, length 4: 37800 SUBNET Option 118, length 4: 10.168.102.0 Subnet-Mask Option 1, length 4: 255.255.255.0 BR Option 28, length 4: 10.168.102.255 Domain-Name-Server Option 6, length 4: dhcp-server.localdomain Default-Gateway Option 3, length 4: 10.168.102.1 Agent-Information Option 82, length 44: Circuit-ID SubOption 1, length 10: ^A^H^@^F^@LO*^@^I Remote-ID SubOption 2, length 6: M-LFM-V!M-)w Unknown SubOption 151, length 10: 0x0000: 0062 6274 2d76 786c 616e Unknown SubOption 11, length 4: 0x0000: 0aa8 6601 Unknown SubOption 5, length 4: 0x0000: 0aa8 6600 END Option 255, length 0 11:18:37.339190 IP (tos 0x10, ttl 254, id 29239, offset 0, flags [none], proto UDP (17), length 374) 22.22.22.21.bootps > dhcp-server.localdomain.bootps: [udp sum ok] BOOTP/DHCP, Request from 00:25:b5:00:00:01 (oui Unknown), length 346, hops 1, xid 0xd2c3606e, Flags [none] (0x0000) Gateway-IP 22.22.22.21 Client-Ethernet-Address 00:25:b5:00:00:01 (oui Unknown) Vendor-rfc1048 Extensions Magic Cookie 0x63825363 DHCP-Message Option 53, length 1: Request Server-ID Option 54, length 4: dhcp-server.localdomain Requested-IP Option 50, length 4: 10.168.102.132 Parameter-Request Option 55, length 18: Subnet-Mask, BR, Time-Zone, Classless-Static-Route Domain-Name, Domain-Name-Server, Hostname, YD YS, NTP, MTU, Option 119 Default-Gateway, Classless-Static-Route, Classless-Static-Route-Microsoft, Static-Route Option 252, NTP Agent-Information Option 82, length 44: Circuit-ID SubOption 1, length 10: ^A^H^@^F^@LO*^@^I Remote-ID SubOption 2, length 6: M-LFM-V!M-)w Unknown SubOption 151, length 10: 0x0000: 0062 6274 2d76 786c 616e Unknown SubOption 11, length 4: 0x0000: 0aa8 6601 Unknown SubOption 5, length 4: 0x0000: 0aa8 6600 END Option 255, length 0 PAD Option 0, length 0, occurs 24 11:18:41.633430 IP (tos 0x10, ttl 254, id 29244, offset 0, flags [none], proto UDP (17), length 374) 22.22.22.21.bootps > dhcp-server.localdomain.bootps: [udp sum ok] BOOTP/DHCP, Request from 00:25:b5:00:00:01 (oui Unknown), length 346, hops 1, xid 0xd2c3606e, Flags [none] (0x0000) Gateway-IP 22.22.22.21 Client-Ethernet-Address 00:25:b5:00:00:01 (oui Unknown) Vendor-rfc1048 Extensions Magic Cookie 0x63825363 DHCP-Message Option 53, length 1: Request Server-ID Option 54, length 4: dhcp-server.localdomain Requested-IP Option 50, length 4: 10.168.102.132 Parameter-Request Option 55, length 18: Subnet-Mask, BR, Time-Zone, Classless-Static-Route Domain-Name, Domain-Name-Server, Hostname, YD YS, NTP, MTU, Option 119 Default-Gateway, Classless-Static-Route, Classless-Static-Route-Microsoft, Static-Route Option 252, NTP Agent-Information Option 82, length 44: Circuit-ID SubOption 1, length 10: ^A^H^@^F^@LO*^@^I Remote-ID SubOption 2, length 6: M-LFM-V!M-)w Unknown SubOption 151, length 10: 0x0000: 0062 6274 2d76 786c 616e Unknown SubOption 11, length 4: 0x0000: 0aa8 6601 Unknown SubOption 5, length 4: 0x0000: 0aa8 6600 END Option 255, length 0 PAD Option 0, length 0, occurs 24 11:18:49.544334 IP (tos 0x10, ttl 254, id 29253, offset 0, flags [none], proto UDP (17), length 374) 22.22.22.21.bootps > dhcp-server.localdomain.bootps: [udp sum ok] BOOTP/DHCP, Request from 00:25:b5:00:00:01 (oui Unknown), length 346, hops 1, xid 0x9a632d2c, Flags [none] (0x0000) Gateway-IP 22.22.22.21 Client-Ethernet-Address 00:25:b5:00:00:01 (oui Unknown) Vendor-rfc1048 Extensions Magic Cookie 0x63825363 DHCP-Message Option 53, length 1: Discover Parameter-Request Option 55, length 18: Subnet-Mask, BR, Time-Zone, Classless-Static-Route Domain-Name, Domain-Name-Server, Hostname, YD YS, NTP, MTU, Option 119 Default-Gateway, Classless-Static-Route, Classless-Static-Route-Microsoft, Static-Route Option 252, NTP Agent-Information Option 82, length 44: Circuit-ID SubOption 1, length 10: ^A^H^@^F^@LO*^@^I Remote-ID SubOption 2, length 6: M-LFM-V!M-)w Unknown SubOption 151, length 10: 0x0000: 0062 6274 2d76 786c 616e Unknown SubOption 11, length 4: 0x0000: 0aa8 6601 Unknown SubOption 5, length 4: 0x0000: 0aa8 6600 END Option 255, length 0 PAD Option 0, length 0, occurs 36 11:18:49.544822 IP (tos 0xc0, ttl 64, id 31785, offset 0, flags [none], proto UDP (17), length 372) dhcp-server.localdomain.bootps > 22.22.22.21.bootps: [bad udp cksum 0x9d58 -> 0x5aed!] BOOTP/DHCP, Reply, length 344, hops 1, xid 0x9a632d2c, Flags [none] (0x0000) Your-IP 10.168.102.132 Server-IP dhcp-server.localdomain Gateway-IP 22.22.22.21 Client-Ethernet-Address 00:25:b5:00:00:01 (oui Unknown) Vendor-rfc1048 Extensions Magic Cookie 0x63825363 DHCP-Message Option 53, length 1: Offer Server-ID Option 54, length 4: 10.168.102.1 Lease-Time Option 51, length 4: 43200 RN Option 58, length 4: 21600 RB Option 59, length 4: 37800 SUBNET Option 118, length 4: 10.168.102.0 Subnet-Mask Option 1, length 4: 255.255.255.0 BR Option 28, length 4: 10.168.102.255 Domain-Name-Server Option 6, length 4: dhcp-server.localdomain Default-Gateway Option 3, length 4: 10.168.102.1 Agent-Information Option 82, length 44: Circuit-ID SubOption 1, length 10: ^A^H^@^F^@LO*^@^I Remote-ID SubOption 2, length 6: M-LFM-V!M-)w Unknown SubOption 151, length 10: 0x0000: 0062 6274 2d76 786c 616e Unknown SubOption 11, length 4: 0x0000: 0aa8 6601 Unknown SubOption 5, length 4: 0x0000: 0aa8 6600 END Option 255, length 0 11:18:49.546102 IP (tos 0x10, ttl 254, id 29254, offset 0, flags [none], proto UDP (17), length 374) 22.22.22.21.bootps > dhcp-server.localdomain.bootps: [udp sum ok] BOOTP/DHCP, Request from 00:25:b5:00:00:01 (oui Unknown), length 346, hops 1, xid 0x9a632d2c, Flags [none] (0x0000) Gateway-IP 22.22.22.21 Client-Ethernet-Address 00:25:b5:00:00:01 (oui Unknown) Vendor-rfc1048 Extensions Magic Cookie 0x63825363 DHCP-Message Option 53, length 1: Request Server-ID Option 54, length 4: dhcp-server.localdomain Requested-IP Option 50, length 4: 10.168.102.132 Parameter-Request Option 55, length 18: Subnet-Mask, BR, Time-Zone, Classless-Static-Route Domain-Name, Domain-Name-Server, Hostname, YD YS, NTP, MTU, Option 119 Default-Gateway, Classless-Static-Route, Classless-Static-Route-Microsoft, Static-Route Option 252, NTP Agent-Information Option 82, length 44: Circuit-ID SubOption 1, length 10: ^A^H^@^F^@LO*^@^I Remote-ID SubOption 2, length 6: M-LFM-V!M-)w Unknown SubOption 151, length 10: 0x0000: 0062 6274 2d76 786c 616e Unknown SubOption 11, length 4: 0x0000: 0aa8 6601 Unknown SubOption 5, length 4: 0x0000: 0aa8 6600 END Option 255, length 0 PAD Option 0, length 0, occurs 24 11:18:56.868214 IP (tos 0x10, ttl 254, id 29262, offset 0, flags [none], proto UDP (17), length 374) 22.22.22.21.bootps > dhcp-server.localdomain.bootps: [udp sum ok] BOOTP/DHCP, Request from 00:25:b5:00:00:01 (oui Unknown), length 346, hops 1, xid 0x9a632d2c, Flags [none] (0x0000) Gateway-IP 22.22.22.21 Client-Ethernet-Address 00:25:b5:00:00:01 (oui Unknown) Vendor-rfc1048 Extensions Magic Cookie 0x63825363 DHCP-Message Option 53, length 1: Request Server-ID Option 54, length 4: dhcp-server.localdomain Requested-IP Option 50, length 4: 10.168.102.132 Parameter-Request Option 55, length 18: Subnet-Mask, BR, Time-Zone, Classless-Static-Route Domain-Name, Domain-Name-Server, Hostname, YD YS, NTP, MTU, Option 119 Default-Gateway, Classless-Static-Route, Classless-Static-Route-Microsoft, Static-Route Option 252, NTP Agent-Information Option 82, length 44: Circuit-ID SubOption 1, length 10: ^A^H^@^F^@LO*^@^I Remote-ID SubOption 2, length 6: M-LFM-V!M-)w Unknown SubOption 151, length 10: 0x0000: 0062 6274 2d76 786c 616e Unknown SubOption 11, length 4: 0x0000: 0aa8 6601 Unknown SubOption 5, length 4: 0x0000: 0aa8 6600 END Option 255, length 0 PAD Option 0, length 0, occurs 24 ^C 13 packets captured 13 packets received by filter 0 packets dropped by kernel [root@dhcp-server ~]# service dnsmasq stop Redirecting to /bin/systemctl stop dnsmasq.service [root@dhcp-server ~]#