nu e datorita rp_filter, am incercat.
Insa am gasit ceva interesant in documentatia de sysctl:

904 <http://www.mjmwired.net/kernel/Documentation/networking/ip-sysctl.txt#904> 
accept_local
- BOOLEAN905 
<http://www.mjmwired.net/kernel/Documentation/networking/ip-sysctl.txt#905>     
           Accept
packets with local source addresses. In combination906
<http://www.mjmwired.net/kernel/Documentation/networking/ip-sysctl.txt#906>     
        with
suitable routing, this can be used to direct packets907
<http://www.mjmwired.net/kernel/Documentation/networking/ip-sysctl.txt#907>     
        between
two local interfaces over the wire and have them908
<http://www.mjmwired.net/kernel/Documentation/networking/ip-sysctl.txt#908>     
        accepted
properly.909 
<http://www.mjmwired.net/kernel/Documentation/networking/ip-sysctl.txt#909>     
   910
<http://www.mjmwired.net/kernel/Documentation/networking/ip-sysctl.txt#910>     
        rp_filter
must be set to a non-zero value in order for911
<http://www.mjmwired.net/kernel/Documentation/networking/ip-sysctl.txt#911>     
        accept_local
to have an effect.912
<http://www.mjmwired.net/kernel/Documentation/networking/ip-sysctl.txt#912>     
913
<http://www.mjmwired.net/kernel/Documentation/networking/ip-sysctl.txt#913>     
        default
FALSE

Acum problema devine "what is suitable routing". Insa de asemenea s-ar
putea sa le primeasca si sa nu raspunda corect.
Cred ca pina la urma tot namespace.
thanks!




2013/2/14 Florin Samareanu <[email protected]>

> Si nu cumva le da drop datorita rp_filter?
>
> Sent from my iPhone
>
> On Feb 14, 2013, at 13:21, alex alex <[email protected]> wrote:
>
> > Da, daca pun arp static catre fiecare ip address prin interfata opusa.
> Vin
> > cereri ICMP req. Nu se trimite reply. Deci probabil kernelul foloseste
> > corect interfata de plecare (ping -I eth0 ), cunoaste ARP si pune
> pachetul
> > pe sirma. Asta ajunge la eth1apoi in kernel care raspunde la ICMP insa
> > probabil ca nu prefera interfata prin care acesta a ajuns fin'ca vede
> > interfata direct conectata.Sau nu raspunde fiindca si-ar raspunde siesi.
> > Cred ca este mai mult de sapat in aceasta directie, asa ca probabil o sa
> > prefer varianta cu namespaces.
> >
> >
> > 2013/2/14 Florin Samareanu <[email protected]>
> >
> >> Tcpdump pe interfata arata ca vin pachetele icmp la destinatie?
> >>
> >> F
> >>
> >> Sent from my iPhone
> >>
> >> On Feb 14, 2013, at 12:53, alex alex <[email protected]> wrote:
> >>
> >>> Da, ma lasa. Acum cunoaste arp dar probabil din acelasi motiv pentru
> care
> >>> nu se raspundea la arp, acum nu raspunde la ICMP.
> >>> E o idee buna, insa rezolva 1/2 din problema. dar e un pas inainte.
> >>> Multumesc.
> >>>
> >>> 2013/2/13 Adrian Popa <[email protected]>
> >>>
> >>>> O altă idee ar putea fi (dacă te lasă) să setezi arp static - MAC-ul
> >> eth0
> >>>> ca fiind învățat prin eth1 și invers. Așa scapi de ARP, în speranța ca
> >>>> verifică dacă are MAC destinație cunoscut înainte să verifice dacă MAC
> >>>> destinație e pe o interfață proprie.
> >>>>
> >>>>
> >>>> 2013/2/13 Florin Samareanu <[email protected]>
> >>>>
> >>>>> Poate e o prostie, dar accept_source_route si rp_filter nu fac ce
> vrei
> >>>> tu?
> >>>>>
> >>>>> Sent from my iPhone
> >>>>>
> >>>>> On Feb 13, 2013, at 17:57, alex alex <[email protected]> wrote:
> >>>>>
> >>>>>> Salut,
> >>>>>> Incerc sa obtin o posibilitate sa masor o conectivitate intre doua
> >>>>>> switchuri avind acces la un singur capat si m-am gindit la urmatorul
> >>>>> set-up:
> >>>>>>
> >>>>>> o statie linux (doua carduri retea), fiecare card conectat in cite
> un
> >>>>> port
> >>>>>> al switch1. Porturile din switch 1 sunt in mod acces, vlan-uri
> >>>> diferite.
> >>>>>> Intre switch 1 si switch 2 am trunk.
> >>>>>> Pe switch 2 am doua porturi configurate in mod acces, cu vlan-urile
> >>>> copie
> >>>>>> din switch 1. Intre aceste doua porturi pun un cross-over (loop).
> Dupa
> >>>> ce
> >>>>>> configurez switch 2 sa fie de acord cu bucla respectiva (!), practic
> >> am
> >>>>>> obtinut o cale looped-back intre port1 din sw1 si port2 din sw2.
> >>>>>>
> >>>>>> Linux                      sw1                            sw2
> >>>>>> ------------   access ------------------     trunk
> >>>> --------------------
> >>>>>> |    eth0|-------------|vlan10         |---------------|
>  vlan10
> >>>>>> |----------|  loop
> >>>>>> |   eth1 |-------------|vlan20         |               |
>  vlan20
> >>>>>> |----------|
> >>>>>> -----------   access -------------------
> >>>>>>  --------------------
> >>>>>>
> >>>>>> Bun. Acum la partea care ma intereseaza. In linux configurez eth0 si
> >>>> eth1
> >>>>>> in acelasi subnet (ex: 192.168.0.1 respectiv 192.168.0.2). Si incerc
> >> sa
> >>>>> fac
> >>>>>> ping cu sursa eth0 in ip eth1.
> >>>>>> Ce obtin: arp initial pleaca asa cum trebuie(de pe eth0), parcurge
> >>>> bucla
> >>>>> si
> >>>>>> intra in eth1. Nu am insa reply la arp. Evident, nici mai departe nu
> >> se
> >>>>> mai
> >>>>>> trimit pachetele ICMP.
> >>>>>> Intrebarea este, pentru cine s-a mai lovit de asa ceva, daca exista
> o
> >>>>>> explicatie. Si evident, daca exista vreo setare (/proc/sys/net?)
> >>>> pentru a
> >>>>>> obtine comportamentul dorit, adica conectivitatea.
> >>>>>> Exista o solutie prin folosirea namespece-urilor care functioneaza
> ok
> >>>>> prin
> >>>>>> punerea celor doua interfete in contexte diferite. Insa macar as
> vrea
> >>>> sa
> >>>>>> inteleg comportamentul prin care kernelul trateaza pachete destinate
> >>>>> catre
> >>>>>> o interfata proprie de retea cind sursa este cunoscuta ca fiind o
> alte
> >>>>>> interfata interna.
> >>>>>> Un link care sa arunce o lumina in aceasta intrebare ar fi
> suficient.
> >>>> Sau
> >>>>>> daca e o intrebare timpita, un motiv pentru care e asa ar fi
> excelent.
> >>>>>> Multumesc.
> >>>>>> _______________________________________________
> >>>>>> RLUG mailing list
> >>>>>> [email protected]
> >>>>>> http://lists.lug.ro/mailman/listinfo/rlug
> >>>>> _______________________________________________
> >>>>> RLUG mailing list
> >>>>> [email protected]
> >>>>> http://lists.lug.ro/mailman/listinfo/rlug
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> >>> _______________________________________________
> >>> RLUG mailing list
> >>> [email protected]
> >>> http://lists.lug.ro/mailman/listinfo/rlug
> >> _______________________________________________
> >> RLUG mailing list
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