* What is so special about 172.31.254.254
@ 2012-04-04 15:25 Gáspár Lajos
2012-04-04 15:55 ` Mike Wright
0 siblings, 1 reply; 6+ messages in thread
From: Gáspár Lajos @ 2012-04-04 15:25 UTC (permalink / raw)
To: netfilter list
Hi list,
I have a strange scenario.
For test reasons I had setup two PC-s.
1. 172.31.254.1
2. 172.31.254.254
Netmask 255.255.255.0
They do not see each other...
But if I change the second IP (for example to 172.31.254.253) then it
all good...
What am I missing?
Swifty
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: What is so special about 172.31.254.254
2012-04-04 15:25 What is so special about 172.31.254.254 Gáspár Lajos
@ 2012-04-04 15:55 ` Mike Wright
2012-04-04 16:05 ` Payam Chychi
2012-04-04 18:52 ` Gáspár Lajos
0 siblings, 2 replies; 6+ messages in thread
From: Mike Wright @ 2012-04-04 15:55 UTC (permalink / raw)
To: Gáspár Lajos; +Cc: netfilter list
On 04/04/2012 08:25 AM, Gáspár Lajos wrote:
> Hi list,
>
> I have a strange scenario.
> For test reasons I had setup two PC-s.
>
> 1. 172.31.254.1
> 2. 172.31.254.254
>
> Netmask 255.255.255.0
>
> They do not see each other...
> But if I change the second IP (for example to 172.31.254.253) then it
> all good...
>
> What am I missing?
Hi Swifty.
Could it be that x.x.x.254 is somewhere defined as a default gateway?
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: What is so special about 172.31.254.254
2012-04-04 15:55 ` Mike Wright
@ 2012-04-04 16:05 ` Payam Chychi
2012-04-04 18:54 ` Gáspár Lajos
2012-04-04 18:52 ` Gáspár Lajos
1 sibling, 1 reply; 6+ messages in thread
From: Payam Chychi @ 2012-04-04 16:05 UTC (permalink / raw)
To: Mike Wright; +Cc: Gáspár Lajos, netfilter list
how are they "not" seeing each other? we talking on layer2, 3, 4, or 7 ?
do you have a local arp table on the system showing the neighboring system?
do you have a transparent firewall in between enforcing layer2 policies?
do you have arp-proxy or gratuitous arp setup on your devices?
-P
On 12-04-04 8:55 AM, Mike Wright wrote:
> On 04/04/2012 08:25 AM, Gáspár Lajos wrote:
>> Hi list,
>>
>> I have a strange scenario.
>> For test reasons I had setup two PC-s.
>>
>> 1. 172.31.254.1
>> 2. 172.31.254.254
>>
>> Netmask 255.255.255.0
>>
>> They do not see each other...
>> But if I change the second IP (for example to 172.31.254.253) then it
>> all good...
>>
>> What am I missing?
>
> Hi Swifty.
>
> Could it be that x.x.x.254 is somewhere defined as a default gateway?
> --
> To unsubscribe from this list: send the line "unsubscribe netfilter" in
> the body of a message to majordomo@vger.kernel.org
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: What is so special about 172.31.254.254
2012-04-04 16:05 ` Payam Chychi
@ 2012-04-04 18:54 ` Gáspár Lajos
0 siblings, 0 replies; 6+ messages in thread
From: Gáspár Lajos @ 2012-04-04 18:54 UTC (permalink / raw)
To: Payam Chychi; +Cc: Mike Wright, netfilter list
Hi Payam
2012-04-04 18:05 keltezéssel, Payam Chychi írta:
> how are they "not" seeing each other? we talking on layer2, 3, 4, or 7 ?
no ping reply at all...
> do you have a local arp table on the system showing the neighboring
> system?
If I change the IP to 253 then it is in the arp list...
> do you have a transparent firewall in between enforcing layer2 policies?
no firewall at all
> do you have arp-proxy or gratuitous arp setup on your devices?
no... it is just a cross cable setup...
Swifty
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: What is so special about 172.31.254.254
2012-04-04 15:55 ` Mike Wright
2012-04-04 16:05 ` Payam Chychi
@ 2012-04-04 18:52 ` Gáspár Lajos
2012-04-04 19:30 ` Ethy H. Brito
1 sibling, 1 reply; 6+ messages in thread
From: Gáspár Lajos @ 2012-04-04 18:52 UTC (permalink / raw)
To: Mike Wright; +Cc: netfilter list
Hi Mike,
>> 1. 172.31.254.1
>> 2. 172.31.254.254
>>
>> Netmask 255.255.255.0
>>
>> They do not see each other...
>> But if I change the second IP (for example to 172.31.254.253) then it
>> all good...
>>
>> What am I missing?
>
> Hi Swifty.
>
> Could it be that x.x.x.254 is somewhere defined as a default gateway?
The default gateway for the first PC (172.31.254.1) is 172.31.254.254...
Swifty
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: What is so special about 172.31.254.254
2012-04-04 18:52 ` Gáspár Lajos
@ 2012-04-04 19:30 ` Ethy H. Brito
0 siblings, 0 replies; 6+ messages in thread
From: Ethy H. Brito @ 2012-04-04 19:30 UTC (permalink / raw)
To: Gáspár Lajos; +Cc: netfilter list
On Wed, 04 Apr 2012 20:52:02 +0200
Gáspár Lajos <swifty@freemail.hu> wrote:
> Hi Mike,
>
> >> 1. 172.31.254.1
> >> 2. 172.31.254.254
> >>
> >> Netmask 255.255.255.0
> >>
> >> They do not see each other...
> >> But if I change the second IP (for example to 172.31.254.253) then it
> >> all good...
> >>
> >> What am I missing?
> >
> > Hi Swifty.
> >
> > Could it be that x.x.x.254 is somewhere defined as a default gateway?
> The default gateway for the first PC (172.31.254.1) is 172.31.254.254...
ping 254.254 from 254.1 and run "tcpdump -ni SOME_IFACE icmp" on *both* PC´s where SOME_IFACE are the interfaces where they talk to each other. Let us know the results.
Ethy
>
> Swifty
>
> --
> To unsubscribe from this list: send the line "unsubscribe netfilter" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
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^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2012-04-04 19:30 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2012-04-04 15:25 What is so special about 172.31.254.254 Gáspár Lajos
2012-04-04 15:55 ` Mike Wright
2012-04-04 16:05 ` Payam Chychi
2012-04-04 18:54 ` Gáspár Lajos
2012-04-04 18:52 ` Gáspár Lajos
2012-04-04 19:30 ` Ethy H. Brito
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