On Wed, Oct 20, 2021 at 10:56:02PM +0200, Geert Stappers wrote: > On Wed, Oct 20, 2021 at 02:48:27PM +0530, Shrenik Bhura wrote: > > On Wed, 20 Oct, 2021, 11:21 Geert Stappers wrote: > > > On Wed, Oct 20, 2021 at 07:50:58AM +0530, Shrenik Bhura wrote: > > > > There isn't anything specific in the configuration that serves the > > > > hostname. I am aware of this feature and when defined it works as > > > > desired. > > > > But when nothing is explicitly defined to serve hostnames, it is > > > > defaulting > > > > to 192 as visible in the logs, and only in the case of an RPi. > > > > When checked on the client with the hostname command, it shows the full > > > > hostname - 192.168.67.53 > > > > > > Such hostname do I call IPaddress. > > > > > > > > > > The same configuration works fine with a x86 system as no hostname is > > > > being > > > > served when none is defined.
Yes, dnsmasq works great. > > > > Have attached the config files involved. > > > > > > Make a packet capture and put the .pcap on a server. > > > Then tell here how to fetch the file. > > > Next can those who care examine the .pcap with their tool. > > > (wireshark / tcpdump) > > > > > > > Once again, do note that this is the case only for an RPi. So there is > > > > some > > > > specific logic in dnsmasq coming into play for an RPi that seems to be > > > > serving the IP address as the default hostname when none is present. > > > > > > So beside the > > > /sbin/tcpdump -w rpi.pcap ether host dc:a6:32:78:98:ae > > > also > > > /sbin/tcpdump -w worksfine.pcap ether host MAC_address_of_known_good > > > > > > > Herein is the link to the related packet captures of an RPi and x86 system > > - > > https://drive.google.com/file/d/11RwpCdbE8W0ohS2QDj4BarZ_VHnEhwfs/view?usp=sharing > > > > The "works fine" is/was captured different as the Raspi capture. > Luckly is the Raspi packet capture the better one, it contains replies. > > What `tshark` says about it. > Note the packet count and the time offset (columns 1 and 2) > and that there are three transactions. > > > |$ tshark -nr rpi.pcap | grep DHCP > | 1 0.000000 0.0.0.0 → 255.255.255.255 DHCP 364 DHCP Discover - > Transaction ID 0x6e9ddeb7 > | 2 0.001666 192.168.67.1 → 192.168.67.53 DHCP 425 DHCP Offer - > Transaction ID 0x6e9ddeb7 > | 3 0.059905 0.0.0.0 → 255.255.255.255 DHCP 351 DHCP Request - > Transaction ID 0x6e9ddeb7 > | 7 0.106212 192.168.67.1 → 192.168.67.53 DHCP 344 DHCP ACK - > Transaction ID 0x6e9ddeb7 > |119315 40.665138 0.0.0.0 → 255.255.255.255 DHCP 590 DHCP Discover - > Transaction ID 0x378f8d8b > |119316 40.668636 192.168.67.1 → 192.168.67.53 DHCP 342 DHCP Offer - > Transaction ID 0x378f8d8b > |119317 40.673119 0.0.0.0 → 255.255.255.255 DHCP 590 DHCP Request - > Transaction ID 0x378f8d8b > |119318 40.727456 192.168.67.1 → 192.168.67.53 DHCP 342 DHCP ACK - > Transaction ID 0x378f8d8b > |119324 44.861769 0.0.0.0 → 255.255.255.255 DHCP 342 DHCP Discover - > Transaction ID 0x6f84b210 > |119325 44.866031 192.168.67.1 → 192.168.67.53 DHCP 342 DHCP Offer - > Transaction ID 0x6f84b210 > |119326 44.866612 0.0.0.0 → 255.255.255.255 DHCP 342 DHCP Request - > Transaction ID 0x6f84b210 > |119327 44.911006 192.168.67.1 → 192.168.67.53 DHCP 343 DHCP ACK - > Transaction ID 0x6f84b210 > |$ > > > Tcpdump Verbose, `-v`, of that: > > $ tcpdump -nr rpi.pcap -v port bootpc > reading from file rpi.pcap, link-type EN10MB (Ethernet), snapshot length > 262144 > 10:48:00.072173 IP (tos 0x0, ttl 64, id 20588, offset 0, flags [none], proto > UDP (17), length 350) > 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from > dc:a6:32:78:98:ae, length 322, xid 0x6e9ddeb7, Flags [none] > Client-Ethernet-Address dc:a6:32:78:98:ae > Vendor-rfc1048 Extensions > Magic Cookie 0x63825363 > DHCP-Message (53), length 1: Discover DHCP Discover > Parameter-Request (55), length 14: > Subnet-Mask (1), Default-Gateway (3), Vendor-Option (43), > Vendor-Class (60) > TFTP (66), BF (67), Unknown (128), Unknown (129) > Unknown (130), Unknown (131), Unknown (132), Unknown (133) > Unknown (134), Unknown (135) > Vendor-Class (60), length 32: "PXEClient:Arch:00000:UNDI:002001" > ARCH (93), length 2: 0 And ARCH 0 is "PC" ... > NDI (94), length 3: 1.2.1 > GUID (97), length 17: > 0.82.80.105.52.18.49.192.0.50.120.152.174.94.119.158.94 > 10:48:00.073839 IP (tos 0xc0, ttl 64, id 5852, offset 0, flags [none], proto > UDP (17), length 411) > 192.168.67.1.67 > 192.168.67.53.68: BOOTP/DHCP, Reply, length 383, xid > 0x6e9ddeb7, Flags [none] > Your-IP 192.168.67.53 > Server-IP 192.168.67.1 > Client-Ethernet-Address dc:a6:32:78:98:ae > Vendor-rfc1048 Extensions > Magic Cookie 0x63825363 > DHCP-Message (53), length 1: Offer DHCP Offer > Server-ID (54), length 4: 192.168.67.1 > Lease-Time (51), length 4: 43200 > BF (67), length 19: "ltsp/undionly.kpxe^@" > RN (58), length 4: 21600 > RB (59), length 4: 37800 > Subnet-Mask (1), length 4: 255.255.255.0 > BR (28), length 4: 192.168.67.255 > Default-Gateway (3), length 4: 192.168.67.1 > Vendor-Class (60), length 9: "PXEClient" > GUID (97), length 17: > 0.82.80.105.52.18.49.192.0.50.120.152.174.94.119.158.94 > Vendor-Option (43), length 44: > 6.1.3.10.4.0.80.88.69.8.7.128.4.1.192.168.67.1.9.23.128.4.20.82.97.115.112.98.101.114.114.121.32.80.105.32.66.111.111.116.32.32.32.255 > 10:48:00.132078 IP (tos 0x0, ttl 64, id 20590, offset 0, flags [none], proto > UDP (17), length 337) > 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from > dc:a6:32:78:98:ae, length 309, xid 0x6e9ddeb7, Flags [none] > Server-IP 192.168.67.1 > Client-Ethernet-Address dc:a6:32:78:98:ae > Vendor-rfc1048 Extensions > Magic Cookie 0x63825363 > DHCP-Message (53), length 1: Request DHCP Request > Requested-IP (50), length 4: 192.168.67.53 > Server-ID (54), length 4: 192.168.67.1 > Vendor-Class (60), length 32: "PXEClient:Arch:00000:UNDI:002001" > GUID (97), length 17: > 0.82.80.105.52.18.49.192.0.50.120.152.174.94.119.158.94 > 10:48:00.178385 IP (tos 0xc0, ttl 64, id 5869, offset 0, flags [none], proto > UDP (17), length 330) > 192.168.67.1.67 > 192.168.67.53.68: BOOTP/DHCP, Reply, length 302, xid > 0x6e9ddeb7, Flags [none] > Your-IP 192.168.67.53 > Server-IP 192.168.67.1 > Client-Ethernet-Address dc:a6:32:78:98:ae > Vendor-rfc1048 Extensions > Magic Cookie 0x63825363 > DHCP-Message (53), length 1: ACK DHCP Acknowledge > Server-ID (54), length 4: 192.168.67.1 > Lease-Time (51), length 4: 43200 > RN (58), length 4: 21600 > RB (59), length 4: 37800 > Subnet-Mask (1), length 4: 255.255.255.0 > BR (28), length 4: 192.168.67.255 > Default-Gateway (3), length 4: 192.168.67.1 > LOG (7), length 4: 192.168.67.1 > Domain-Name-Server (6), length 8: 8.8.8.8,8.8.8.8 First "DHCP Cycle" is complete. Next DHCP Cycle starts. > 10:48:40.737311 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP > (17), length 576) > 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from > dc:a6:32:78:98:ae, length 548, xid 0x378f8d8b, Flags [none] > Client-Ethernet-Address dc:a6:32:78:98:ae > Vendor-rfc1048 Extensions > Magic Cookie 0x63825363 > DHCP-Message (53), length 1: Discover DHCP Discover > Parameter-Request (55), length 9: > Subnet-Mask (1), Default-Gateway (3), Domain-Name-Server (6), > Hostname (12) > Domain-Name (15), RP (17), MTU (26), YD (40) > NTP (42) > 10:48:40.740809 IP (tos 0xc0, ttl 64, id 3785, offset 0, flags [none], proto > UDP (17), length 328) > 192.168.67.1.67 > 192.168.67.53.68: BOOTP/DHCP, Reply, length 300, xid > 0x378f8d8b, Flags [none] > Your-IP 192.168.67.53 > Server-IP 192.168.67.1 > Client-Ethernet-Address dc:a6:32:78:98:ae > Vendor-rfc1048 Extensions > Magic Cookie 0x63825363 > DHCP-Message (53), length 1: Offer DHCP Offer > Server-ID (54), length 4: 192.168.67.1 > Lease-Time (51), length 4: 43200 > RN (58), length 4: 21600 > RB (59), length 4: 37800 > Subnet-Mask (1), length 4: 255.255.255.0 > BR (28), length 4: 192.168.67.255 > Default-Gateway (3), length 4: 192.168.67.1 > Domain-Name-Server (6), length 8: 8.8.8.8,8.8.8.8 > 10:48:40.745292 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP > (17), length 576) > 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from > dc:a6:32:78:98:ae, length 548, xid 0x378f8d8b, Flags [none] > Client-Ethernet-Address dc:a6:32:78:98:ae > Vendor-rfc1048 Extensions > Magic Cookie 0x63825363 > DHCP-Message (53), length 1: Request DHCP Request > Server-ID (54), length 4: 192.168.67.1 > Requested-IP (50), length 4: 192.168.67.53 > Parameter-Request (55), length 9: > Subnet-Mask (1), Default-Gateway (3), Domain-Name-Server (6), > Hostname (12) > Domain-Name (15), RP (17), MTU (26), YD (40) > NTP (42) > 10:48:40.799629 IP (tos 0xc0, ttl 64, id 3788, offset 0, flags [none], proto > UDP (17), length 328) > 192.168.67.1.67 > 192.168.67.53.68: BOOTP/DHCP, Reply, length 300, xid > 0x378f8d8b, Flags [none] > Your-IP 192.168.67.53 > Server-IP 192.168.67.1 > Client-Ethernet-Address dc:a6:32:78:98:ae > Vendor-rfc1048 Extensions > Magic Cookie 0x63825363 > DHCP-Message (53), length 1: ACK DHCP Acknowledge > Server-ID (54), length 4: 192.168.67.1 > Lease-Time (51), length 4: 43200 > RN (58), length 4: 21600 > RB (59), length 4: 37800 > Subnet-Mask (1), length 4: 255.255.255.0 > BR (28), length 4: 192.168.67.255 > Default-Gateway (3), length 4: 192.168.67.1 > Domain-Name-Server (6), length 8: 8.8.8.8,8.8.8.8 Second "DHCP Cycle" is complete. > |119318 40.727456 192.168.67.1 → 192.168.67.53 DHCP 342 DHCP ACK - > Transaction ID 0x378f8d8b > } Five ICMPv6 packets > |119324 44.861769 0.0.0.0 → 255.255.255.255 DHCP 342 DHCP Discover - > Transaction ID 0x6f84b210 Next DHCP Cycle starts. > 10:48:44.933942 IP (tos 0x10, ttl 128, id 0, offset 0, flags [none], proto > UDP (17), length 328) > 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from > dc:a6:32:78:98:ae, length 300, xid 0x6f84b210, Flags [none] > Client-Ethernet-Address dc:a6:32:78:98:ae > Vendor-rfc1048 Extensions > Magic Cookie 0x63825363 > DHCP-Message (53), length 1: Discover DHCP Discover > Hostname (12), length 13: "192.168.67.53" Client says "My hostname is '192.168.67.53'" > Parameter-Request (55), length 13: > Subnet-Mask (1), BR (28), Time-Zone (2), Default-Gateway (3) > Domain-Name (15), Domain-Name-Server (6), Unknown (119), Hostname > (12) > Netbios-Name-Server (44), Netbios-Scope (47), MTU (26), > Classless-Static-Route (121) > NTP (42) > 10:48:44.938204 IP (tos 0xc0, ttl 64, id 3933, offset 0, flags [none], proto > UDP (17), length 328) > 192.168.67.1.67 > 192.168.67.53.68: BOOTP/DHCP, Reply, length 300, xid > 0x6f84b210, Flags [none] > Your-IP 192.168.67.53 > Server-IP 192.168.67.1 > Client-Ethernet-Address dc:a6:32:78:98:ae > Vendor-rfc1048 Extensions > Magic Cookie 0x63825363 > DHCP-Message (53), length 1: Offer DHCP Offer > Server-ID (54), length 4: 192.168.67.1 > Lease-Time (51), length 4: 43200 > RN (58), length 4: 21600 > RB (59), length 4: 37800 > Subnet-Mask (1), length 4: 255.255.255.0 > BR (28), length 4: 192.168.67.255 > Default-Gateway (3), length 4: 192.168.67.1 > Domain-Name-Server (6), length 8: 8.8.8.8,8.8.8.8 > 10:48:44.938785 IP (tos 0x10, ttl 128, id 0, offset 0, flags [none], proto > UDP (17), length 328) > 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from > dc:a6:32:78:98:ae, length 300, xid 0x6f84b210, Flags [none] > Client-Ethernet-Address dc:a6:32:78:98:ae > Vendor-rfc1048 Extensions > Magic Cookie 0x63825363 > DHCP-Message (53), length 1: Request DHCP Request > Server-ID (54), length 4: 192.168.67.1 > Requested-IP (50), length 4: 192.168.67.53 > Hostname (12), length 13: "192.168.67.53" Client says "My hostname is '192.168.67.53'" > Parameter-Request (55), length 13: > Subnet-Mask (1), BR (28), Time-Zone (2), Default-Gateway (3) > Domain-Name (15), Domain-Name-Server (6), Unknown (119), Hostname > (12) > Netbios-Name-Server (44), Netbios-Scope (47), MTU (26), > Classless-Static-Route (121) > NTP (42) > 10:48:44.983179 IP (tos 0xc0, ttl 64, id 3934, offset 0, flags [none], proto > UDP (17), length 329) > 192.168.67.1.67 > 192.168.67.53.68: BOOTP/DHCP, Reply, length 301, xid > 0x6f84b210, Flags [none] > Your-IP 192.168.67.53 > Server-IP 192.168.67.1 > Client-Ethernet-Address dc:a6:32:78:98:ae > Vendor-rfc1048 Extensions > Magic Cookie 0x63825363 > DHCP-Message (53), length 1: ACK DHCP Acknowledge > Server-ID (54), length 4: 192.168.67.1 > Lease-Time (51), length 4: 43200 > RN (58), length 4: 21600 > RB (59), length 4: 37800 > Subnet-Mask (1), length 4: 255.255.255.0 > BR (28), length 4: 192.168.67.255 > Default-Gateway (3), length 4: 192.168.67.1 > Hostname (12), length 3: "192" Server says "Your hostname is '192'" > Domain-Name-Server (6), length 8: 8.8.8.8,8.8.8.8 > > > More in the next message. Done "in line" Back to: > > > On Wed, Oct 20, 2021 at 07:50:58AM +0530, Shrenik Bhura wrote: > > > > There isn't anything specific in the configuration that serves the > > > > hostname. I am aware of this feature and when defined it works as > > > > desired. Acknowledge on "it works as desired". > > > > But when nothing is explicitly defined to serve hostnames, > > > > it is defaulting to 192 as visible in the logs, There I tent to disagree. > > > > and only in the case of an RPi. I do read that as "There are some more factors. There are yet unknown factors." > > > > When checked on the client with the hostname command, > > > > it shows the full hostname - 192.168.67.53 Yes. And the question is: How did it get there? Groeten Geert Stappers -- Silence is hard to parse
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