Table of Contents
Tracing PUBLIC RAC device for DHCP requests –
- our DHCP server is running on port 67
[root@gract1 cvutrace]# tcpdump -i eth1 -vvv -s 1500 port 67 .. gract1.example.com.bootpc > 255.255.255.255.bootps: [bad udp cksum 473!] BOOTP/DHCP, Request from 00:00:00:00:00:00 (oui Ethernet), length 368, xid 0xab536e31, Flags [Broadcast] (0x8000) Client-Ethernet-Address 00:00:00:00:00:00 (oui Ethernet) sname "gract-scan1-vip" Vendor-rfc1048 Extensions Magic Cookie 0x63825363 DHCP-Message Option 53, length 1: Discover MSZ Option 57, length 2: 8 Client-ID Option 61, length 16: "gract-scan1-vip" END Option 255, length 0 PAD Option 0, length 0, occurs 102 11:25:25.480234 IP (tos 0x10, ttl 128, id 0, offset 0, flags [none], proto UDP (17), length 335) ns1.example.com.bootps > 255.255.255.255.bootpc: [udp sum ok] BOOTP/DHCP, Reply, length 307, xid 0xab536e31, Flags [Broadcast] (0x8000) Your-IP 192.168.5.150 Client-Ethernet-Address 00:00:00:00:00:00 (oui Ethernet) Vendor-rfc1048 Extensions Magic Cookie 0x63825363 DHCP-Message Option 53, length 1: Offer Server-ID Option 54, length 4: ns1.example.com Lease-Time Option 51, length 4: 21600 Subnet-Mask Option 1, length 4: 255.255.255.0 Default-Gateway Option 3, length 4: 192.168.5.1 Domain-Name-Server Option 6, length 4: ns1.example.com Time-Zone Option 2, length 4: -19000 IPF Option 19, length 1: N RN Option 58, length 4: 10800 RB Option 59, length 4: 18900 NTP Option 42, length 4: ns1.example.com BR Option 28, length 4: 192.168.5.255 END Option 255, length 0 11:25:25.481129 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.5.153 tell ns1.example.com, length 46 11:25:25.484070 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 396) gract1.example.com.bootpc > ns1.example.com.bootps: [bad udp cksum 8780!] BOOTP/DHCP, Request from 00:00:00:00:00:00 (oui Ethernet), length 368, xid 0x7f90997b, Flags [Broadcast] (0x8000) Client-IP 192.168.5.150 Your-IP 192.168.5.150 Client-Ethernet-Address 00:00:00:00:00:00 (oui Ethernet) sname "gract-scan1-vip" Vendor-rfc1048 Extensions Magic Cookie 0x63825363 DHCP-Message Option 53, length 1: Release Server-ID Option 54, length 4: ns1.example.com Client-ID Option 61, length 16: "gract-scan1-vip" END Option 255, length 0 PAD Option 0, length 0, occurs 100