Date: Fri, 22 May 1998 13:01:40 +1000 (EST) From: michael@one.com.au To: freebsd-questions@FreeBSD.ORG Message-ID: <199805220301.NAA24398@one.one.com.au>
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Could this be the problem:
Machine A connects to the Internet via his local ISP using PPP -ddial... This
ISP is the default route for this machine (i.e. say the interface tun0
represents this underlying connection). Now, when machine A connects to
machine B (via PPP TCP), I want to swap the default route on A to machine B.
It seems that PPP works fine, but when I come to ping B from A, nothing
happens. Is it because the underlying interface (i.e. tun0), which would have
been required by PPP TCP to establish the initial connection, has had its entry
in the routing table replaced with the newer tunnel connection.
It seems that if I do a normal PPP connection between the machines (i.e.
without changing the default route, the machines communicate over the tunnel
connection fine). It is when I try to make this tunnel the default route for
machine A everything falls down.
Initially (everything OK at this stage):
default (tun0) default (tun0)
ISP <---------------- A B ----------------> ISP
TCP PPP connection from A to B (OK):
(tun1)
|-------------------------------------------------|
| default (tun0) | default (tun0)
|-- ISP <---------------- A |--> B ----------------> ISP
TCP PPP connection from A to B where B is A's default (NOT OK)
default (tun1)
|-------------------------------------------------|
| (tun0) | default (tun0)
|-- ISP <---------------- A |--> B ----------------> ISP
I did a TCP dump at both ends with the last scenario, where basically the ICMP
requests go out but no replies come back. Also, I checked ppp.log and
everything is OK there to. I think the problem may lie in the routing tables
themselves, and not with PPP itself. What do u think.
Cheers again, Michael!
>> From: brian@awfulhak.org
>> To: michael@one.com.au
>> Things look fine.
>>
>> Try `set log +tcp/ip' on each end to see if you're receiving the
>> data. You can also `set log +async' for a look at the raw data and
>> `show mem' to see if ppp's just sitting on the incoming data.
> Synopsis:
>
> Basically, I am trying to use PPP over TCP to connect two machines, say A
and
> B, where A is the initiator and B is the receiver. When A connects to B, I
> want A to make B its default router. It seems that ppp is able to
> successfully negotiate IP Addresses and update the routing tables
accordingly.
> However, when I try to ping machine B (10.0.0.135) from A, an ICMP request
is
> sent, but no reply.
>
> Basically, on machine A, I used the following command to connect:
>
> ppp -background pppin
>
> and on B
>
> sitting on a port... ppp -direct pppin
>
> Can you tell me why ppp seems to establish the link correctly, but then
> everything falls to pieces. Oh yeah, I'm using FreeBSD 2.2.5!
>
> Machine A's setup (similar to B, without changing of default route)
>
> %more ppp.linkup
> pppin:
> delete 0
> add 0 0 HISADDR
>
> %inconfig -a
> tun0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1500
> inet 10.0.0.136 --> 10.0.0.135 netmask 0xffffff00
>
> %netstat -r
> Routing tables
>
> Internet:
> Destination Gateway Flags Refs Use Netif
Expire
> default 10.0.0.135 UGSc 1 0 tun0
> 10.0.0.135 10.0.0.136 UH 2 27 tun0
>
> Thanks in advance,
> Michael!
>
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--
Brian <brian@Awfulhak.org>, <brian@FreeBSD.org>, <brian@OpenBSD.org>
<http://www.Awfulhak.org>;
Don't _EVER_ lose your sense of humour....
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