Networking problem

[JD]

On 05/15/11 17:35, JB wrote:
> JB<jb.1234abcd<at>  gmail.com>  writes:
>
>> ....
>              M1
>              192.168.1.x/24
>              eth?
>               |
> =================================================
>                          |
>           192.168.1.254/24 wireless router
>                  ^                    ^
>                  ^                    ^
>                  ^                    ^(wireless)
>                  ^                    ^
>               wlan0:0               en1
>               192.168.1.108/24      192.168.1.70/24
>               wlan0                 Powerbook (OS/X)
>               fe80::234::...
>               Fedora
>
> You said:
> Fedora can ping M1 and wireless router.
> Powerbook can ping M1 and wireless router.
> Fedora and Powerbook can not ping each other.
> Fedora has open firewall, Powerbook has no firewall.
>
> ------------------
> On Fedora Machine:
> ------------------
> # /sbin/ifconfig
> ...
> wlan0     Link encap:Ethernet  HWaddr 00:34:56:00:03:43
>             inet6 addr: fe80::234:56ff:fe00:343/64 Scope:Link
>             UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>            ...
> wlan0:0   Link encap:Ethernet  HWaddr 00:34:56:00:03:43
>             inet addr:192.168.1.108  Bcast:192.168.1.255  Mask:255.255.255.0
>             UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>
> # /bin/netstat -rn
> Kernel IP routing table
> Destination     Gateway         Genmask         Flags   MSS Window  irtt
> Iface
> ...
> 192.168.1.0     0.0.0.0         255.255.255.0   U         0 0          0
> wlan0
> ...
> 0.0.0.0         192.168.1.254   0.0.0.0         UG        0 0          0
> wlan0
>
> So:
> Fedora can ping M1 and wireless router.
> I assume via network 192.168.1.0 destination and wlan0.
> We do not know anything about M1's eth? interface config and routing table
> with regard to IPV4 and/or IPv6, so the analysis will be a bit shallow.
> But, the situation is curious, because we have ping's IPv4-format packet with
> FROM IPv4 address and TO IPv4 address going out thru IPv6-type interface :-)

No!! The router has ipv6 disabled.
Fedora has IPV6 also disabled, so does the
Powerbook.

Machine M1 does not have it disabled per se'
but is not using it on it's connection to the
router, because as I indicated, the router has
IPV6 disabled.


> The machine does not care, just pushes it out the wire :-) Right ?
> The reply will be a IPv4-format packet as well, but will come back to Fedora
> on interface that will depend on how M1 routing table is configured (it could
> look like Fedora's, or not) ...
>
> NOTE: it would be good to use tcpdump entry, watch both interfaces wlan0 and
> wlan0:0 on Fedora, and see on which one the ping's request and reply packets
> will be processed.
>
> --------------------
> On Powerbook machine
> --------------------
> # /sbin/ifconfig
> ...
> en1: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST>  mtu 1500
>       inet 192.168.1.70 netmask 0xffffff00 broadcast 192.168.1.255
>       ether 00:11:24:92:bc:e0
>
> # /sbin/netstat -rn
> Routing tables
> Internet:
> Destination        Gateway            Flags    Refs      Use  Netif Expire
> default            192.168.1.254      UGSc        8        0    en1
> 127                127.0.0.1          UCS         0        0    lo0
> 127.0.0.1          127.0.0.1          UH          0        4    lo0
> 169.254            link#6             UCS         0        0    en1
> 192.168.1          link#6             UCS         2        0    en1
> 192.168.1.1        0:26:18:6:ef:7     UHLW        0      113    en1    566
> 192.168.1.60       127.0.0.1          UHS         0        0    lo0
> 192.168.1.254      0:1d:5a:c8:91:c1   UHLW       15      153    en1    565
>
> So:
> Powerbook can ping M1 and wireless router.
> I assume via default route and en1, and IPv4.
>
> So, where is the problem with Fedora and Powerbook not being able to see
> each other ?
>
> Let's try a ping from Fedora to Powerbook.
> Here we do not know everything about Fedora's and Powerbooki's interfaces
> config and routing tables with regard to IPV4 and/or IPv6.
> After usual shouting who has 192.168.1.70, the Powerbook answers and arp
> sets up a IP-to-MAC translation item in its table. All is ready to send
> the packet.
> But, the situation is curious, because we have ping's IPv4-format packet with
> FROM IPv4 address and TO IPv4 address going out thru IPv6-type interface :-)
> The machine does not care, just pushes it out the wire :-) Right ?
> The reply will be a IPv4-format packet as well, and will come back to Fedora
> on interface wlan0:0, which is not the same as IPv4 request's interface IPv6-
> type wlan0.
> Is here any problem with IPv4, IPv6, and interfaces mismatch ? Routing table
> misconfiguration in Fedora (IPv4-type IPs vice IPv6-type interfaces) ?
>
> NOTE: it would be good to use tcpdump entry, watch both interfaces wlan0 and
> wlan0:0 on Fedora, and see on which one the ping's request and reply packets
> will be processed.
>
> Btw:
> - have you tried a different machine in place of that Powerbook ?
> - with regard to layer-2 "ping" tool not functioning
>    There is a possibility to use arp-poisoning tool to manufacture layer 2
>    frames with MAC headers you specify.
>    You will probably not get an "echo" back, but if you put a sniffer on
>    the far segment, you should be able to determine whether your manufactured
>    frames make it to the other side.
>      http://www.mail-archive.com/cisco@groupstudy.com/msg79833.html
>
> JB
>
> Maria Callas - "Violetta Aria" - La Traviata
> http://www.youtube.com/watch?v=hv5hCEf8qSw
>
>
Your questions are trying to involve IPv6 and I repeat:
There is no IPV6 in the equation :)

Humbug! Just firgedaboudit :)