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Zdravim vospolok,

riesim jeden problem s dost specifickymi poziadavkami na konektivitu virtualnej masiny beziacej na virtualboxe, ktora ma network interface zbrigdovany na eth0 interface na hoste. Velmi mi to nejde a napady dochadzaju, preto dufam, ze mie niekto bude schopny pomoct.

Na fyzickej masine (debian) mam nahodenu virtualku s bridgovanym interfacom na eth0 interface na hostovi.

Problemom je, ze switch overuje MAC adresy voci whitelistu a len vyvolene MAC adresy sa dostanu do spravnej VLANy, kde DHCP server vyslysi prosby o pridelenie IP adresy.

Dalsim obmedzenim je, ze na jeden port na switchi moze byt pripojena len jedna "whitelistovana" MAC adresa.

Vo fyzickom hoste mam sietovu kartu vyhradenu pre pouzitie virtualkami, jej MAC adresa je vo whiteliste a host ju nijako nepouziva.

root@host:~# ip a
2: eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN qlen 1000
    link/ether b0:48:7a:81:15:58 brd ff:ff:ff:ff:ff:ff

relevantne nastavenia virtualnej masiny:

virtualbox@host:~$ VBoxManage showvminfo client
NIC 1:           MAC: 080027959BD1, Attachment: Bridged Interface 'eth0', Cable connected: on, Trace: off (file: none), Type: 82540EM, Reported speed: 0 Mbps, Boot priority: 0, Promisc Policy: deny

Potrebujem zabezpecit, aby vsetka prevadzka vychadzajuca z eth0 na hostovi mala ako source MAC adresu prave adresu fyzickej karty.

skusil som na hostovi nastavit toto:

PHYS_MAC="b0:48:7a:81:15:58"
VIRT_MAC="08:00:27:95:9B:D1"

ebtables -t nat -A POSTROUTING -o eth0 -j snat --to-src $PHYS_MAC --snat-arp --snat-target ACCEPT
ebtables -t nat -A PREROUTING -i eth0  -j dnat --to-dst $VIRT_MAC --dnat-target ACCEPT

avsak vysledok sa nedostavil, klient stale nedostava IP adresu od DHCP klienta

vypis z tcpdumpu (neviem nakolko je relevantny, nie som si isty v ktorom mieste odchytava pakety, ci pred, alebo az za postroutingom...

root@host:~# tcpdump -i eth0
tcpdump: WARNING: eth0: no IPv4 address assigned
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes
...
22:06:49.300151 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 08:00:27:95:9b:d1 (oui Unknown), length 300
22:06:49.300174 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 08:00:27:95:9b:d1 (oui Unknown), length 300
22:07:03.294648 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 08:00:27:95:9b:d1 (oui Unknown), length 300
22:07:03.294674 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 08:00:27:95:9b:d1 (oui Unknown), length 300
...
^C
136 packets captured
136 packets received by filter
0 packets dropped by kernel

Mate nejake napady ako tento problem vyriesit? Nemusim nutne pouzit MAC maskaradu, rozmyslal som nad nastavenim MAC adresy fyzickeho adaptera aj pre virtualny, no nie som si isty ako by sa bridge zachoval, keby na oboch jeho koncoch boli adaptery s rovnakou MAC adresou...

Vdaka za (akukolvek) pomoc.