Re: [LARTC] Why 'ping' only succeed in one direction?

From: shen jing <jshen@cad.zju.edu.cn>
To: lartc@vger.kernel.org
Subject: Re: [LARTC] Why 'ping' only succeed in one direction?
Date: Wed, 30 May 2001 08:40:54 +0000	[thread overview]
Message-ID: <marc-lartc-99122225404362@msgid-missing> (raw)
In-Reply-To: <marc-lartc-99114800203883@msgid-missing>

> Thank you very much.

I've checked the file , they have the following content:

/proc/sys/net/ipv4/conf/all/rp_filter       :    1
/proc/sys/net/ipv4/conf/default/rp_filter:    0
/proc/sys/net/ipv4/conf/eth0/rp_filter:        0
/proc/sys/net/ipv4/conf/lo/rp_filter:            0

the ip route  says:

[root@cad166 lo]# ip route
192.168.1.0/24 dev eth0  proto kernel  scope link  src 192.168.1.1
210.32.131.0/24 dev eth0  proto kernel  scope link  src 210.32.131.166
127.0.0.0/8 dev lo  scope link
default via 210.32.131.1 dev eth0
default via 210.32.131.1 dev eth0  src 210.32.131.166  metric 1
[root@cad166 lo]#

I don't understand what's  the files under  all/  and default/ for.
And the tcpdump on linuxbox and snoop on Sun both shows
icmp echo request and icmp echo reply has been received.
But why 'ping 210.32.131.97' always show nothing when executed
on 192.168.1.8?

James Shen

> Hi
> seems ok check /proc/sys/net/ipv4/conf/[*]/rp_filter
> what it does is explained in the adv routing howto almost at the end.
>
> Hope it helps
>
> bye
>
> > ----------------------------------- ( Ethernet)
> >
> >
> > Sun-1              Linux              Sun-2
> > 210.32.131.97  192.168.1.1(eth0)    192.168.1.8
> >                210.32.131.166(eth0:0)
> >
> > Routing table :
> >
> >    Sun-1:    192.168.1.0/24   ---> 210.32.131.166
> >                     default -----> 210.32.131.2
> >
> >    Linux  :    default---> 210.32.131.2
> >               ( I add no explicit routing  table about the twodirect
> >                connected network )
> >
> >   Sun-2 :    default --> 192.168.1.1
>
> On Tuesday 29 May 2001 11:53 am, shen jing wrote:
> > Hi:
> >
> > I'm using a linux box ( Rh7.1 ) as a router which connect two Solaris2.6
> >
> > box.
> > The three computer is interconnected by ethernet, each computer has
> > only on ethernet adapter.
> >
> > The following is my network connection :
> >
> > ----------------------------------- ( Ethernet)
> >
> >
> > Sun-1              Linux              Sun-2
> > 210.32.131.97  192.168.1.1(eth0)    192.168.1.8
> >                210.32.131.166(eth0:0)
> >
> > Routing table :
> >
> >    Sun-1:    192.168.1.0/24   ---> 210.32.131.166
> >                     default -----> 210.32.131.2
> >
> >    Linux  :    default---> 210.32.131.2
> >               ( I add no explicit routing  table about the twodirect
> >                connected network )
> >
> >   Sun-2 :    default --> 192.168.1.1
> >
> > While I exec "ping 192.168.1.8 "on Sun-1, it succeed, with 0% packet
> > loss.
> >
> > But when I exec  "ping 210.32.131.97" on Sun-2, the ping always hang
> > with no output, when I interrupt it with "Ctl-C', it shows "100% packet
> > loss".
> >
> > I do tcpdump on linux and snoop on Sun to find out what happened, but
> > all detailed record shows "ICMP echo requect/reply " has been delivered
> > between Sun-1<-->linux, Linux<-->Sun-2
> >
> > And I can telnet/ftp between Sun-1 & Sun-2.
> >
> > Is there someone will do me a favor to explain why this happens ? Is
> > there any configuration error with my linux box ?
> >
> > Thanks in advance and each word will be highly appreciated.
> >
> > James Shen
> >

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