DHCP Client Problem INTRANET

[TimHaegele]

Hallo Zusammen,

ich habe hier ein etwas seltsames Problem das ich gerne wie folgt schildern möchte:

In einem Rechenzentrum werden die IPs per DHCP für beide Schnittstellen INTRANET und WAN verwendet. Wir wollen wollen hier den vRouter (aktuellste Version 10.50RU6 )einsetzen und haben dazu die Schnittstellen DSL-1 und LAN-1 jeweils als DHCP-Client konfiguriert. Das funktioniert im Fall ETH-1->DSL-1 perfekt.

An der ETH-2->LAN-1 (INTRANET) wird vom DHCP-Server allerdings keine Adresse bezogen. In wireshark sieht es so aus als ob eine Aushandlung stattfindet,und auch vom DHCP Server die IP-Informationen und Optionen übermittelt werden, aber der Lancom übernimmt diese nie. (Dazu vll später mehr, falls gewünscht).
Versuchsweise, habe ich die ETH-2 als DSL-2 mit DHCP (DHCPOE) konfiguriert und siehe da, es wird direkt eine IP-Adresse bezogen und die Kommunikation intern funktioniert (mit den Einschränkungen einer WAN-Verbindung).

Gibt es dafür eine einfache Erklärung oder werden mehr Informationen benötigt?

Danke und Gruß
Tim

PS: Im Anhang ist ein Screenshot mit der aktiven Routing Tabelle wobei die INTRANET Schnittstelle als "Internet" konfiguriert wurde.

INTRANET-als-WAN.png

[backslash]

Hi TimHaegele

Gibt es dafür eine einfache Erklärung oder werden mehr Informationen benötigt?

die "einfache" Erklärung wäre: "irgendwas ist falsch konfiguriert"...
Scherz beiseite...
Der erste Schritt wäre ein DHCP-Trace, um zu sehen, warum das nicht funktioniert...

Gruß
Backslash

[TimHaegele]

Hier Auszüge aus tr # DHCP:



DEVICE: LANCOM vRouter
HW-RELEASE: 0
VERSION: 10.50.0725RU6 / 11.03.2022


[DHCP] 2022/03/21 14:56:07,404 Devicetime: 2022/03/21 14:55:36,980
Starting autodetection phase


[DHCP] 2022/03/21 14:56:13,659 Devicetime: 2022/03/21 14:55:43,230 [info] : DHCP Client Tx (LAN, INTRANET)
DHCP Client Message (request): DHCPREQUEST
Op = 01 | HType = 01 | HLen = 06 | Hops = 00
XId = aa7c537a | Secs = 077e | Flags = 8000
CIAdr = 0.0.0.0 | YIAdr = 0.0.0.0
SIAdr = 0.0.0.0 | GIAdr = 0.0.0.0
CHAdr = 86 00 00 08 3b 73 00 00 00 00 00 00 00 00 00 00
Message-Type (53): request (3)
Client-ID (61): ETH:86:00:00:08:3b:73
Message-Size (57): 1280
Server-ID (54): 192.168.98.1
Requested-IP (50): 192.168.98.2
Hostname (12): LANCOM-2425e2
Vendor-Class-ID (60): 4c 41 4e 43 4f 4d 20 76 52 6f 75 74 65 72
Option List (55): 1, 121, 3, 6, 15, 43


[DHCP] 2022/03/21 14:56:41,517 Devicetime: 2022/03/21 14:56:11,118
DHCP Aging
DHCP Aging complete


[DHCP] 2022/03/21 14:56:46,285 Devicetime: 2022/03/21 14:56:15,876 [info] : DHCP Client: set state idle (0) for INTRANET


[DHCP] 2022/03/21 14:56:57,177 Devicetime: 2022/03/21 14:56:26,788 [info] : DHCP Client: set state init (1) for INTRANET

[DHCP] 2022/03/21 14:56:57,287 Devicetime: 2022/03/21 14:56:26,888 [info] : DHCP Client: set state selecting (2) for INTRANET

[DHCP] 2022/03/21 14:56:57,287 Devicetime: 2022/03/21 14:56:26,888 [info] : DHCP Client Tx (LAN, INTRANET)
DHCP Client Message (request): DHCPDISCOVER
Op = 01 | HType = 01 | HLen = 06 | Hops = 00
XId = 9ec8ed38 | Secs = 07cb | Flags = 8000
CIAdr = 0.0.0.0 | YIAdr = 0.0.0.0
SIAdr = 0.0.0.0 | GIAdr = 0.0.0.0
CHAdr = 86 00 00 08 3b 73 00 00 00 00 00 00 00 00 00 00
Message-Type (53): discover (1)
Client-ID (61): ETH:86:00:00:08:3b:73
Message-Size (57): 1280
Hostname (12): LANCOM-2425e2
Vendor-Class-ID (60): 4c 41 4e 43 4f 4d 20 76 52 6f 75 74 65 72
Option List (55): 1, 121, 3, 6, 15, 43

[DHCP] 2022/03/21 14:56:57,349 Devicetime: 2022/03/21 14:56:26,902 [info] : DHCP Client Rx (LAN, INTRANET)
DHCP Server Message (reply): DHCPOFFER
Op = 02 | HType = 01 | HLen = 06 | Hops = 00
XId = 9ec8ed38 | Secs = 0000 | Flags = 0000
CIAdr = 0.0.0.0 | YIAdr = 192.168.98.2
SIAdr = 192.168.98.1 | GIAdr = 0.0.0.0
CHAdr = 86 00 00 08 3b 73 00 00 00 00 00 00 00 00 00 00
Message-Type (53): offer (2)
Netmask (1): 255.255.255.255
Gateway (3): 192.168.98.1
Server-ID (54): 192.168.98.1
LeaseTime (51): 86400
Classless Static Route (121):
Length: 17
192.168.98.1/32-0.0.0.0
192.168.98.0/24-192.168.98.1

unknown (249): 20 c0 a8 62 01 00 00 00 00 18 c0 a8 62 c0 a8 62
01
unknown (26): 05 aa


[DHCP] 2022/03/21 14:57:01,478 Devicetime: 2022/03/21 14:56:31,084
Starting autodetection phase

[DHCP] 2022/03/21 14:57:02,472 Devicetime: 2022/03/21 14:56:32,070 [info] : DHCP Client: set state requesting (3) for INTRANET

[DHCP] 2022/03/21 14:57:02,472 Devicetime: 2022/03/21 14:56:32,070 [info] : DHCP Client Tx (LAN, INTRANET)
DHCP Client Message (request): DHCPREQUEST
Op = 01 | HType = 01 | HLen = 06 | Hops = 00
XId = 9ec8ed38 | Secs = 07cb | Flags = 8000
CIAdr = 0.0.0.0 | YIAdr = 0.0.0.0
SIAdr = 0.0.0.0 | GIAdr = 0.0.0.0
CHAdr = 86 00 00 08 3b 73 00 00 00 00 00 00 00 00 00 00
Message-Type (53): request (3)
Client-ID (61): ETH:86:00:00:08:3b:73
Message-Size (57): 1280
Server-ID (54): 192.168.98.1
Requested-IP (50): 192.168.98.2
Hostname (12): LANCOM-2425e2
Vendor-Class-ID (60): 4c 41 4e 43 4f 4d 20 76 52 6f 75 74 65 72
Option List (55): 1, 121, 3, 6, 15, 43


[DHCP] 2022/03/21 14:57:07,525 Devicetime: 2022/03/21 14:56:37,116 [info] : DHCP Client Tx (LAN, INTRANET)
DHCP Client Message (request): DHCPREQUEST
Op = 01 | HType = 01 | HLen = 06 | Hops = 00
XId = 9ec8ed38 | Secs = 07cb | Flags = 8000
CIAdr = 0.0.0.0 | YIAdr = 0.0.0.0
SIAdr = 0.0.0.0 | GIAdr = 0.0.0.0
CHAdr = 86 00 00 08 3b 73 00 00 00 00 00 00 00 00 00 00
Message-Type (53): request (3)
Client-ID (61): ETH:86:00:00:08:3b:73
Message-Size (57): 1280
Server-ID (54): 192.168.98.1
Requested-IP (50): 192.168.98.2
Hostname (12): LANCOM-2425e2
Vendor-Class-ID (60): 4c 41 4e 43 4f 4d 20 76 52 6f 75 74 65 72
Option List (55): 1, 121, 3, 6, 15, 43


[DHCP] 2022/03/21 14:57:17,265 Devicetime: 2022/03/21 14:56:46,886 [info] : DHCP Client Tx (LAN, INTRANET)
DHCP Client Message (request): DHCPREQUEST
Op = 01 | HType = 01 | HLen = 06 | Hops = 00
XId = 9ec8ed38 | Secs = 07cb | Flags = 8000
CIAdr = 0.0.0.0 | YIAdr = 0.0.0.0
SIAdr = 0.0.0.0 | GIAdr = 0.0.0.0
CHAdr = 86 00 00 08 3b 73 00 00 00 00 00 00 00 00 00 00
Message-Type (53): request (3)
Client-ID (61): ETH:86:00:00:08:3b:73
Message-Size (57): 1280
Server-ID (54): 192.168.98.1
Requested-IP (50): 192.168.98.2
Hostname (12): LANCOM-2425e2
Vendor-Class-ID (60): 4c 41 4e 43 4f 4d 20 76 52 6f 75 74 65 72
Option List (55): 1, 121, 3, 6, 15, 43


[DHCP] 2022/03/21 14:57:32,280 Devicetime: 2022/03/21 14:57:01,907 [info] : DHCP Client Tx (LAN, INTRANET)
DHCP Client Message (request): DHCPREQUEST
Op = 01 | HType = 01 | HLen = 06 | Hops = 00
XId = 9ec8ed38 | Secs = 07cb | Flags = 8000
CIAdr = 0.0.0.0 | YIAdr = 0.0.0.0
SIAdr = 0.0.0.0 | GIAdr = 0.0.0.0
CHAdr = 86 00 00 08 3b 73 00 00 00 00 00 00 00 00 00 00
Message-Type (53): request (3)
Client-ID (61): ETH:86:00:00:08:3b:73
Message-Size (57): 1280
Server-ID (54): 192.168.98.1
Requested-IP (50): 192.168.98.2
Hostname (12): LANCOM-2425e2
Vendor-Class-ID (60): 4c 41 4e 43 4f 4d 20 76 52 6f 75 74 65 72
Option List (55): 1, 121, 3, 6, 15, 43


[DHCP] 2022/03/21 14:57:41,482 Devicetime: 2022/03/21 14:57:11,118
DHCP Aging
DHCP Aging complete


[DHCP] 2022/03/21 14:58:03,261 Devicetime: 2022/03/21 14:57:32,912 [info] : DHCP Client: set state idle (0) for INTRANET


[DHCP] 2022/03/21 14:58:13,435 Devicetime: 2022/03/21 14:57:43,099
Starting autodetection phase

[DHCP] 2022/03/21 14:58:14,376 Devicetime: 2022/03/21 14:57:44,038 [info] : DHCP Client: set state init (1) for INTRANET

[DHCP] 2022/03/21 14:58:14,547 Devicetime: 2022/03/21 14:57:44,138 [info] : DHCP Client: set state selecting (2) for INTRANET

[DHCP] 2022/03/21 14:58:14,547 Devicetime: 2022/03/21 14:57:44,138 [info] : DHCP Client Tx (LAN, INTRANET)
DHCP Client Message (request): DHCPDISCOVER
Op = 01 | HType = 01 | HLen = 06 | Hops = 00
XId = ff90f8f5 | Secs = 0819 | Flags = 8000
CIAdr = 0.0.0.0 | YIAdr = 0.0.0.0
SIAdr = 0.0.0.0 | GIAdr = 0.0.0.0
CHAdr = 86 00 00 08 3b 73 00 00 00 00 00 00 00 00 00 00
Message-Type (53): discover (1)
Client-ID (61): ETH:86:00:00:08:3b:73
Message-Size (57): 1280
Hostname (12): LANCOM-2425e2
Vendor-Class-ID (60): 4c 41 4e 43 4f 4d 20 76 52 6f 75 74 65 72
Option List (55): 1, 121, 3, 6, 15, 43

[DHCP] 2022/03/21 14:58:14,547 Devicetime: 2022/03/21 14:57:44,148 [info] : DHCP Client Rx (LAN, INTRANET)
DHCP Server Message (reply): DHCPOFFER
Op = 02 | HType = 01 | HLen = 06 | Hops = 00
XId = ff90f8f5 | Secs = 0000 | Flags = 0000
CIAdr = 0.0.0.0 | YIAdr = 192.168.98.2
SIAdr = 192.168.98.1 | GIAdr = 0.0.0.0
CHAdr = 86 00 00 08 3b 73 00 00 00 00 00 00 00 00 00 00
Message-Type (53): offer (2)
Netmask (1): 255.255.255.255
Gateway (3): 192.168.98.1
Server-ID (54): 192.168.98.1
LeaseTime (51): 86400
Classless Static Route (121):
Length: 17
192.168.98.1/32-0.0.0.0
192.168.98.0/24-192.168.98.1

unknown (249): 20 c0 a8 62 01 00 00 00 00 18 c0 a8 62 c0 a8 62
01
unknown (26): 05 aa


[DHCP] 2022/03/21 14:58:19,743 Devicetime: 2022/03/21 14:57:49,390 [info] : DHCP Client: set state requesting (3) for INTRANET

[DHCP] 2022/03/21 14:58:19,743 Devicetime: 2022/03/21 14:57:49,390 [info] : DHCP Client Tx (LAN, INTRANET)
DHCP Client Message (request): DHCPREQUEST
Op = 01 | HType = 01 | HLen = 06 | Hops = 00
XId = ff90f8f5 | Secs = 0819 | Flags = 8000
CIAdr = 0.0.0.0 | YIAdr = 0.0.0.0
SIAdr = 0.0.0.0 | GIAdr = 0.0.0.0
CHAdr = 86 00 00 08 3b 73 00 00 00 00 00 00 00 00 00 00
Message-Type (53): request (3)
Client-ID (61): ETH:86:00:00:08:3b:73
Message-Size (57): 1280
Server-ID (54): 192.168.98.1
Requested-IP (50): 192.168.98.2
Hostname (12): LANCOM-2425e2
Vendor-Class-ID (60): 4c 41 4e 43 4f 4d 20 76 52 6f 75 74 65 72
Option List (55): 1, 121, 3, 6, 15, 43


[DHCP] 2022/03/21 14:58:23,864 Devicetime: 2022/03/21 14:57:53,516 [info] : DHCP Client Tx (LAN, INTRANET)
DHCP Client Message (request): DHCPREQUEST
Op = 01 | HType = 01 | HLen = 06 | Hops = 00
XId = ff90f8f5 | Secs = 0819 | Flags = 8000
CIAdr = 0.0.0.0 | YIAdr = 0.0.0.0
SIAdr = 0.0.0.0 | GIAdr = 0.0.0.0
CHAdr = 86 00 00 08 3b 73 00 00 00 00 00 00 00 00 00 00
Message-Type (53): request (3)
Client-ID (61): ETH:86:00:00:08:3b:73
Message-Size (57): 1280
Server-ID (54): 192.168.98.1
Requested-IP (50): 192.168.98.2
Hostname (12): LANCOM-2425e2
Vendor-Class-ID (60): 4c 41 4e 43 4f 4d 20 76 52 6f 75 74 65 72
Option List (55): 1, 121, 3, 6, 15, 43


[DHCP] 2022/03/21 14:58:31,443 Devicetime: 2022/03/21 14:58:01,101 [info] : DHCP Client Tx (LAN, INTRANET)
DHCP Client Message (request): DHCPREQUEST
Op = 01 | HType = 01 | HLen = 06 | Hops = 00
XId = ff90f8f5 | Secs = 0819 | Flags = 8000
CIAdr = 0.0.0.0 | YIAdr = 0.0.0.0
SIAdr = 0.0.0.0 | GIAdr = 0.0.0.0
CHAdr = 86 00 00 08 3b 73 00 00 00 00 00 00 00 00 00 00
Message-Type (53): request (3)
Client-ID (61): ETH:86:00:00:08:3b:73
Message-Size (57): 1280
Server-ID (54): 192.168.98.1
Requested-IP (50): 192.168.98.2
Hostname (12): LANCOM-2425e2
Vendor-Class-ID (60): 4c 41 4e 43 4f 4d 20 76 52 6f 75 74 65 72
Option List (55): 1, 121, 3, 6, 15, 43


[DHCP] 2022/03/21 14:58:41,448 Devicetime: 2022/03/21 14:58:11,118
DHCP Aging
DHCP Aging complete


[DHCP] 2022/03/21 14:58:47,863 Devicetime: 2022/03/21 14:58:17,538 [info] : DHCP Client Tx (LAN, INTRANET)
DHCP Client Message (request): DHCPREQUEST
Op = 01 | HType = 01 | HLen = 06 | Hops = 00
XId = ff90f8f5 | Secs = 0819 | Flags = 8000
CIAdr = 0.0.0.0 | YIAdr = 0.0.0.0
SIAdr = 0.0.0.0 | GIAdr = 0.0.0.0
CHAdr = 86 00 00 08 3b 73 00 00 00 00 00 00 00 00 00 00
Message-Type (53): request (3)
Client-ID (61): ETH:86:00:00:08:3b:73
Message-Size (57): 1280
Server-ID (54): 192.168.98.1
Requested-IP (50): 192.168.98.2
Hostname (12): LANCOM-2425e2
Vendor-Class-ID (60): 4c 41 4e 43 4f 4d 20 76 52 6f 75 74 65 72
Option List (55): 1, 121, 3, 6, 15, 43


[DHCP] 2022/03/21 14:59:05,544 Devicetime: 2022/03/21 14:58:35,217
Starting autodetection phase


[DHCP] 2022/03/21 14:59:19,856 Devicetime: 2022/03/21 14:58:49,553 [info] : DHCP Client: set state idle (0) for INTRANET


[DHCP] 2022/03/21 14:59:29,618 Devicetime: 2022/03/21 14:58:59,320 [info] : DHCP Client: set state init (1) for INTRANET

[DHCP] 2022/03/21 14:59:29,710 Devicetime: 2022/03/21 14:58:59,420 [info] : DHCP Client: set state selecting (2) for INTRANET

[DHCP] 2022/03/21 14:59:29,710 Devicetime: 2022/03/21 14:58:59,420 [info] : DHCP Client Tx (LAN, INTRANET)
DHCP Client Message (request): DHCPDISCOVER
Op = 01 | HType = 01 | HLen = 06 | Hops = 00
XId = 54177395 | Secs = 0864 | Flags = 8000
CIAdr = 0.0.0.0 | YIAdr = 0.0.0.0
SIAdr = 0.0.0.0 | GIAdr = 0.0.0.0
CHAdr = 86 00 00 08 3b 73 00 00 00 00 00 00 00 00 00 00
Message-Type (53): discover (1)
Client-ID (61): ETH:86:00:00:08:3b:73
Message-Size (57): 1280
Hostname (12): LANCOM-2425e2
Vendor-Class-ID (60): 4c 41 4e 43 4f 4d 20 76 52 6f 75 74 65 72
Option List (55): 1, 121, 3, 6, 15, 43

[DHCP] 2022/03/21 14:59:29,788 Devicetime: 2022/03/21 14:58:59,435 [info] : DHCP Client Rx (LAN, INTRANET)
DHCP Server Message (reply): DHCPOFFER
Op = 02 | HType = 01 | HLen = 06 | Hops = 00
XId = 54177395 | Secs = 0000 | Flags = 0000
CIAdr = 0.0.0.0 | YIAdr = 192.168.98.2
SIAdr = 192.168.98.1 | GIAdr = 0.0.0.0
CHAdr = 86 00 00 08 3b 73 00 00 00 00 00 00 00 00 00 00
Message-Type (53): offer (2)
Netmask (1): 255.255.255.255
Gateway (3): 192.168.98.1
Server-ID (54): 192.168.98.1
LeaseTime (51): 86400
Classless Static Route (121):
Length: 17
192.168.98.1/32-0.0.0.0
192.168.98.0/24-192.168.98.1

unknown (249): 20 c0 a8 62 01 00 00 00 00 18 c0 a8 62 c0 a8 62
01
unknown (26): 05 aa


[DHCP] 2022/03/21 14:59:35,291 Devicetime: 2022/03/21 14:59:04,999 [info] : DHCP Client: set state requesting (3) for INTRANET

[DHCP] 2022/03/21 14:59:35,291 Devicetime: 2022/03/21 14:59:04,999 [info] : DHCP Client Tx (LAN, INTRANET)
DHCP Client Message (request): DHCPREQUEST
Op = 01 | HType = 01 | HLen = 06 | Hops = 00
XId = 54177395 | Secs = 0864 | Flags = 8000
CIAdr = 0.0.0.0 | YIAdr = 0.0.0.0
SIAdr = 0.0.0.0 | GIAdr = 0.0.0.0
CHAdr = 86 00 00 08 3b 73 00 00 00 00 00 00 00 00 00 00
Message-Type (53): request (3)
Client-ID (61): ETH:86:00:00:08:3b:73
Message-Size (57): 1280
Server-ID (54): 192.168.98.1
Requested-IP (50): 192.168.98.2
Hostname (12): LANCOM-2425e2
Vendor-Class-ID (60): 4c 41 4e 43 4f 4d 20 76 52 6f 75 74 65 72
Option List (55): 1, 121, 3, 6, 15, 43

[DHCP] 2022/03/21 14:59:38,943 Devicetime: 2022/03/21 14:59:08,649 [info] : DHCP Client Tx (LAN, INTRANET)
DHCP Client Message (request): DHCPREQUEST
Op = 01 | HType = 01 | HLen = 06 | Hops = 00
XId = 54177395 | Secs = 0864 | Flags = 8000
CIAdr = 0.0.0.0 | YIAdr = 0.0.0.0
SIAdr = 0.0.0.0 | GIAdr = 0.0.0.0
CHAdr = 86 00 00 08 3b 73 00 00 00 00 00 00 00 00 00 00
Message-Type (53): request (3)
Client-ID (61): ETH:86:00:00:08:3b:73
Message-Size (57): 1280
Server-ID (54): 192.168.98.1
Requested-IP (50): 192.168.98.2
Hostname (12): LANCOM-2425e2
Vendor-Class-ID (60): 4c 41 4e 43 4f 4d 20 76 52 6f 75 74 65 72
Option List (55): 1, 121, 3, 6, 15, 43

[DHCP] 2022/03/21 14:59:41,401 Devicetime: 2022/03/21 14:59:11,119
DHCP Aging
DHCP Aging complete


[TraceStopped] 2022/03/21 14:59:47,049
Used config:
# Trace config
trace + DHCP

# Show commands

[backslash]

Hi TimHaegele

die Verhandlung fängt zwar an: Das LANCOM schickt eien DISCOVER und der Server ein OFFER - seoweit so gut...
Dann schickt das LANCOM ein REQUEST, aber der Servber antwortet darauf nicht mehr... Da müßte vom Server eiun ACK kommen. Hier hat also der DHCP-Server ein Problem...

Kann es sein, daß der Server nicht damit umgehen kann, daß das LANCOM im DHCP-Header in den Flags das "Broadcast" Bit (0x8000) gesetzt hat? Wenn ein Client das anfordert, dann MUSS der DHCP-Server das ACK als Broadcast schicken, denn der Client akzeptiert "gerichtete" Antworten erst, wenn er auch eine IP-Adresse hat... (hier beißt sich die Katze also irgendwie in den Schwanz)

Das LANCOM ist im LAN auch zwingend darauf angewiesen, daß das ACK als Broadcast kommt. Im WAN hingegen funktioniert es auch um Unicast-Mode, da ein WAN-Interface den "Protokoll-Verhandlungs"-Zustand hat, in dem es einfach alles akzeptiert

Wenn du also keinen Einfluß auf den DHCP-Server hast, dann wirst du mit der WAN-Krücke leben oder aber dem LANCOM eine feste IP-Adresse geben müssen - was ganz nebenbei auch die einzig RFC konforme Betriebsart eines Routers wäre...

Gruß
Backslash

[TimHaegele]

Hallo Backslash,

danke für ausführlich Info. Ich habe diese mal ans RZ weitergeleitet, vll können die behilflich sein.

Das manuelle anlegen der LAN Adressen und Routen hat mir auch größere Probleme bereitet, dazu später mehr in einem neuen Thread.

Gruß
Tim