ppp dialin server

ppp dialin server

Post by David Funnel » Thu, 16 May 2002 15:41:08



Hi

I am setting up a redhat 7.3 ppp dialin server for my local network.
I can get the modems to connect. But I cannot get the remote computer to
ping inside the network. timeout mesage

remote computer (win98 laptop) ip is X.X.X.249 (specified in
/etc/ppp/options.ttyS0)
serial port on ppp server is X.X.X.248 (specified in
/etc/ppp/options.ttyS0)
ethernet card on ppp server (connecting to LAN) is X.X.X.240

remote computer can ping serial port on ppp server, it can also ping to
ethernet card on same server.
But I cannot ping any other computers on the LAN. I have set ipchains
rules on the ppp server to accept and forward any packets from remote
computer. I did notice the gateway address on the win98 laptop is its
own address (X.X.X.249). I could not change this even when I manually
specified another gateway address.

I have used the same subnet ip numbers for the lot. Sould the serial
port address and remote address need to be separate subnet??

I am stumped any comments appreciated.

cheers Dave

 
 
 

ppp dialin server

Post by Martin Dase » Thu, 16 May 2002 19:53:55



> Hi

> I am setting up a redhat 7.3 ppp dialin server for my local network.
> I can get the modems to connect. But I cannot get the remote computer to
> ping inside the network. timeout mesage

> remote computer (win98 laptop) ip is X.X.X.249 (specified in
> /etc/ppp/options.ttyS0)
> serial port on ppp server is X.X.X.248 (specified in
> /etc/ppp/options.ttyS0)
> ethernet card on ppp server (connecting to LAN) is X.X.X.240

what subnet masks are you using on the interfaces?
it seems you are using the same subnet (X.X.X) on both interfaces of the
ppp server. so routing gets confused.
there is only one interface, to which the pppserver directs ip packets
for subnet X.X.X and this seems to be the lan interface.

make sute to use a different subnet for the ppp "network" (y.y.y.249 and
y.y.y.248)

Quote:

> remote computer can ping serial port on ppp server, it can also ping to
> ethernet card on same server.

the laptop's default route seems to be the ppp interface, and once on
the ppp interface it reaches the ppp server and finally the lan interface.

Quote:> But I cannot ping any other computers on the LAN.

well you can ping them, and icmp echo request get to the destination,
but the answer icmp echo reply won't get routed back to your laptop

Quote:> I have set ipchains
> rules on the ppp server to accept and forward any packets from remote
> computer. I did notice the gateway address on the win98 laptop is its
> own address (X.X.X.249). I could not change this even when I manually
> specified another gateway address.

> I have used the same subnet ip numbers for the lot. Sould the serial
> port address and remote address need to be separate subnet??

yep! se above!

Quote:> I am stumped any comments appreciated.

> cheers Dave

i hope this helps! let me know!

-- martin :-)

--
--
Kind Regards
        Martin Daser
-----

-----
"Technology is just another word for it doesn't work yet" - D. Adams

 
 
 

ppp dialin server

Post by Clifford Kit » Thu, 16 May 2002 23:37:23



> I am setting up a redhat 7.3 ppp dialin server for my local network.
> I can get the modems to connect. But I cannot get the remote computer to
> ping inside the network. timeout mesage

Never seen a "timeout" message from ping.  Post the exact message if
I don't guess right in the comments that follow.

Quote:> remote computer (win98 laptop) ip is X.X.X.249 (specified in
> /etc/ppp/options.ttyS0)
> serial port on ppp server is X.X.X.248 (specified in
> /etc/ppp/options.ttyS0)
> ethernet card on ppp server (connecting to LAN) is X.X.X.240

I take it that all the X.X.X's represent the same network.

Make the IP address specifier in options.ttyS0 this:

:X.X.X.249

and make sure that the server-side pppd does not have the noipdefault
option.  This will let pppd use the Ethernet IP address X.X.X.240 for
the PPP interface address, which is perfectly okay.  Make sure that the
pppd proxyarp option is in options.ttyS0.

Quote:> remote computer can ping serial port on ppp server, it can also ping to
> ethernet card on same server.
> But I cannot ping any other computers on the LAN. I have set ipchains
> rules on the ppp server to accept and forward any packets from remote
> computer. I did notice the gateway address on the win98 laptop is its
> own address (X.X.X.249). I could not change this even when I manually
> specified another gateway address.

I don't know Windows, but I do know that, during the PPP connection,
the default route on the laptop must be though the PPP interface to
get to the Internet.  A network-work specific route through the PPP
interface to the peer's LAN may be used if you only want to access
hosts on the peer's LAN.  Even the network-specific route is not
necessary in order to access hosts on the LAN if the laptop has no
existing route that includes that LAN's subnet.

Why there is a default route on the laptop through the PPP interface
that uses the laptop's IP address for the PPP link (X.X.X.249) as a
gateway, as you seem to have said, is beyond me.

Quote:> I have used the same subnet ip numbers for the lot. Sould the serial
> port address and remote address need to be separate subnet??

I don't fully understand this question, but I think the answer is no.
The IP address for the PPP connection on the laptop should be on the
same subnet as that used for the peer's LAN.

--

PPP-Q&A links, downloads:    http://users3.ev1.net/~ckite/public_html/
/* My confidence in this answer (X), on a scale of 0 to 10:
   |----|----|----|----|----|----|----|----|----|----X
   0----1----2----3----4----5----6----7----8----9----10 */

 
 
 

ppp dialin server

Post by Bill Unr » Wed, 22 May 2002 03:11:34


]> Hi
]>
]> I am setting up a redhat 7.3 ppp dialin server for my local network.
]> I can get the modems to connect. But I cannot get the remote computer to
]> ping inside the network. timeout mesage
]>
]> remote computer (win98 laptop) ip is X.X.X.249 (specified in
]> /etc/ppp/options.ttyS0)
]> serial port on ppp server is X.X.X.248 (specified in
]> /etc/ppp/options.ttyS0)
]> ethernet card on ppp server (connecting to LAN) is X.X.X.240

]what subnet masks are you using on the interfaces?
]it seems you are using the same subnet (X.X.X) on both interfaces of the
]ppp server. so routing gets confused.

Why should it get confused? The routing information includes the
interface. It is prefectly OK to use the same subnets etc, as long as
you specify the routing in sufficient detail.

]there is only one interface, to which the pppserver directs ip packets
]for subnet X.X.X and this seems to be the lan interface.

]make sute to use a different subnet for the ppp "network" (y.y.y.249 and
]y.y.y.248)

No need.

 
 
 

ppp dialin server

Post by Martin Dase » Wed, 22 May 2002 15:16:15




> ]what subnet masks are you using on the interfaces?
> ]it seems you are using the same subnet (X.X.X) on both interfaces of the
> ]ppp server. so routing gets confused.

> Why should it get confused? The routing information includes the
> interface. It is prefectly OK to use the same subnets etc, as long as
> you specify the routing in sufficient detail.

if you have 2 interfaces, e.g.
192.168.0.10/24 on eth0 and 192.168.0.12/24 on eth2, which have the same
subnet.
now you want to send a packet to 192.168.0.17, how should IP know where
to send it? IP will usually will pick the first entry in the routing
table (which might be right or wrong, depending on your network topology)

well this leads to 2 different solutions:
1. apply host based routing, which is a big effort, because you have to
add any host to the routing table.

2. apply a subnet mask (e.g. 255.255.255.128 or so), and this is what i
mentioned (you actually create different subnets)

Quote:

> ]there is only one interface, to which the pppserver directs ip packets
> ]for subnet X.X.X and this seems to be the lan interface.

> ]make sute to use a different subnet for the ppp "network" (y.y.y.249 and
> ]y.y.y.248)

> No need.

--
--
Kind Regards
        Martin Daser
-----

-----
"Technology is just another word for it doesn't work yet" - D. Adams
 
 
 

ppp dialin server

Post by Martin Dase » Wed, 22 May 2002 15:20:32




> ]what subnet masks are you using on the interfaces?
> ]it seems you are using the same subnet (X.X.X) on both interfaces of the
> ]ppp server. so routing gets confused.

> Why should it get confused? The routing information includes the
> interface. It is prefectly OK to use the same subnets etc, as long as
> you specify the routing in sufficient detail.

if you have 2 interfaces, e.g.
192.168.0.10/24 on eth0 and 192.168.0.12/24 on eth2, which have the same
subnet.
now you want to send a packet to 192.168.0.17, how should IP know where
to send it? IP will usually will pick the first entry in the routing
table (which might be right or wrong, depending on your network topology)

well this leads to 2 different solutions:
1. apply host based routing, which is a big effort, because you have to
add any host to the routing table. well i agree, it works ... but for
what costs ...

2. apply a subnet mask (e.g. 255.255.255.128 or so), and this is what i
mentioned (you actually create different subnets)

Quote:

> ]there is only one interface, to which the pppserver directs ip packets
> ]for subnet X.X.X and this seems to be the lan interface.

> ]make sute to use a different subnet for the ppp "network" (y.y.y.249 and
> ]y.y.y.248)

> No need.

--
--
Kind Regards
        Martin Daser
-----

-----
"Technology is just another word for it doesn't work yet" - D. Adams
 
 
 

ppp dialin server

Post by David Funnel » Wed, 22 May 2002 16:10:30


Thanks Martin, Clifford and Bill for your replies but I am still banging my
head against a wall.

summary
LAN with subnet X.X.10.0, with a redhat 7.3 ppp dial in server to provice LAN
access to a remote laptop.
The ppp connection is established and I can ping from remote laptop to ppp
server. But the remote computer cannot ping rest of the LAN nor can the rest
of LAN see laptop.

I have enabled IP forwarding and made ipchains rules totally open. ( for the
moment)

As I see it there are two options with ip addressing.

OPTION 1 SAME SUBNET
Give the ppp interface and remote computer addresses from the same subnet as
the rest of LAN (X.X.10.0)
In this case proxyarp needs to be working for packets to travel via the ppp
server.
I have put this option in
/etc/ppp/options.yyyS0
proxyarp

But when I manually check the arp table there are no entries. I tried manually
adding entries using the arp command but despite specifying a specific mac
address,  the arp entry would have a * character.

OPTION 2 DIFFERENT SUBNET
Give the ppp interface (X.X.11.1) and the remote computer (X.X.11.2) a
separate subnet.
My undestanding is that in this case I do not need proxyarp but the route
table to direct the traffic through the ppp server.
remote(X.X.11.2)  can ping server ppp (X.X.11.1) and also server eth0
(X.X.10.240) but nothing else on LAN

I am still learning about routing so any comments on this routing table would
be appreciated

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
X.X.11.2    *               255.255.255.255 UH    0      0        0 ppp0
X.X.10.0    *               255.255.255.0   U     0      0        0 eth0
127.0.0.0       *               255.0.0.0       U     0      0        0 lo
default         X.X.10.1    0.0.0.0         UG    0      0        0 eth0

cheers Dave



> > Hi

> > I am setting up a redhat 7.3 ppp dialin server for my local network.
> > I can get the modems to connect. But I cannot get the remote computer to
> > ping inside the network. timeout mesage

> > remote computer (win98 laptop) ip is X.X.X.249 (specified in
> > /etc/ppp/options.ttyS0)
> > serial port on ppp server is X.X.X.248 (specified in
> > /etc/ppp/options.ttyS0)
> > ethernet card on ppp server (connecting to LAN) is X.X.X.240

> what subnet masks are you using on the interfaces?
> it seems you are using the same subnet (X.X.X) on both interfaces of the
> ppp server. so routing gets confused.
> there is only one interface, to which the pppserver directs ip packets
> for subnet X.X.X and this seems to be the lan interface.

> make sute to use a different subnet for the ppp "network" (y.y.y.249 and
> y.y.y.248)

> > remote computer can ping serial port on ppp server, it can also ping to
> > ethernet card on same server.

> the laptop's default route seems to be the ppp interface, and once on
> the ppp interface it reaches the ppp server and finally the lan interface.

> > But I cannot ping any other computers on the LAN.

> well you can ping them, and icmp echo request get to the destination,
> but the answer icmp echo reply won't get routed back to your laptop

> > I have set ipchains
> > rules on the ppp server to accept and forward any packets from remote
> > computer. I did notice the gateway address on the win98 laptop is its
> > own address (X.X.X.249). I could not change this even when I manually
> > specified another gateway address.

> > I have used the same subnet ip numbers for the lot. Sould the serial
> > port address and remote address need to be separate subnet??

> yep! se above!

> > I am stumped any comments appreciated.

> > cheers Dave

> i hope this helps! let me know!

> -- martin :-)

> --
> --
> Kind Regards
>         Martin Daser
> -----

> -----
> "Technology is just another word for it doesn't work yet" - D. Adams

 
 
 

ppp dialin server

Post by Martin Dase » Wed, 22 May 2002 23:25:16


--- truncated ---

Quote:

> OPTION 1 SAME SUBNET
> Give the ppp interface and remote computer addresses from the same subnet as
> the rest of LAN (X.X.10.0)
> In this case proxyarp needs to be working for packets to travel via the ppp
> server.
> I have put this option in
> /etc/ppp/options.yyyS0
> proxyarp

> But when I manually check the arp table there are no entries. I tried manually
> adding entries using the arp command but despite specifying a specific mac
> address,  the arp entry would have a * character.

> OPTION 2 DIFFERENT SUBNET
> Give the ppp interface (X.X.11.1) and the remote computer (X.X.11.2) a
> separate subnet.
> My undestanding is that in this case I do not need proxyarp but the route
> table to direct the traffic through the ppp server.
> remote(X.X.11.2)  can ping server ppp (X.X.11.1) and also server eth0
> (X.X.10.240) but nothing else on LAN

> I am still learning about routing so any comments on this routing table would
> be appreciated

> Kernel IP routing table
> Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
> X.X.11.2    *               255.255.255.255 UH    0      0        0 ppp0
> X.X.10.0    *               255.255.255.0   U     0      0        0 eth0
> 127.0.0.0   *               255.0.0.0       U     0      0        0 lo
> default         X.X.10.1    0.0.0.0         UG    0      0        0 eth0

> cheers Dave

ok this seems to be your configuration, right?

+---------------+     +-------------------------+        +-------------+
| server        |     | dial in server / router |        | laptop      |
| X.X.10.240/24 |     | X.X.10.1/24 X.X.11.1/32 |        | X.X.11.2/32 |
|     eth0      |     |  eth0           ppp0    |        |    ppp0     |
+------+--------+     +---+--------------+------+        +-----+-------+
        |    ethernet      |              |                     |
     ---+------------------+---           +-------+             |
                                                  /      ppp    |
                                                 +--------------+

you should be able to ping:
1. X.X.11.1 from the laptop, ok?
2. X.X.11.2 from the router, ok?
3. X.X.10.1 from the server, ok?
4. X.X.10.240 from the router, ok?

now packets from X.X.10.1 to X.X.10.240 must be forwarded by the router
machine
the routing table says:
-packets for network X.X.10 (line 2) shall be forwarded to interface eth0
-packets for network X.X.11.2 (line 1, host route) should be forwarded
to interface ppp0
-anythink else (skip loopback) will be directed to eth0 (line 4, default
route)this
looks fine for me! this is how i would set it up anyway ...

Now that you have to disclose the Xs in the addresses. If they are from
a private pool(192.168 ... etc), IP does not have to forward them! see
rfc??? (i forgot)

--
Kind Regards
        Martin Daser
-----

-----
"Technology is just another word for it doesn't work yet" - D. Adams

 
 
 

ppp dialin server

Post by Clifford Kit » Thu, 23 May 2002 01:25:09



> OPTION 1 SAME SUBNET
> Give the ppp interface and remote computer addresses from the same
> subnet as the rest of LAN (X.X.10.0) In this case proxyarp needs
> to be working for packets to travel via the ppp server.

Correct.

Quote:> I have put this option in
> /etc/ppp/options.yyyS0
> proxyarp

I hope you meant /etc/ppp/options.ttyS0 (and ttyS0 is the modem's device
file), otherwise the yyyS0 is wrong and it certainly won't work...

Providing the client with an IP address on the LAN's subnet is the easist
way to go.  Using an IP address not on the LAN means that proxyarp won't
work and you'll have to go to more trouble.

Quote:> But when I manually check the arp table there are no entries. I tried
> manually adding entries using the arp command but despite specifying
> a specific mac address,  the arp entry would have a * character.

It's been awhile since I set up a PPP host to accept calls, but the
proxy arp tables for the Ethernet interface may not show any entries
until a host on the LAN ARP's for the laptop IP address.

You can use "tcpdump -i eth0" to see if there are any ARP requests
being generated with a PPP connection.

Quote:> Kernel IP routing table
> Destination     Gateway         Genmask     Flags Metric Ref    Use Iface
> X.X.11.2    *               255.255.255.255 UH    0      0        0 ppp0
> X.X.10.0    *               255.255.255.0   U     0      0        0 eth0
> 127.0.0.0       *           255.0.0.0       U     0      0        0 lo
> default         X.X.10.1    0.0.0.0         UG    0      0        0 eth0

This is for the case where the laptop has an IP address not on the LAN,
which won't work without implementing routing on other hosts, or running
a routing daemon on all LAN hosts, to make it happen.

The default route shown above is not necessary for communication with
the LAN and looks to me like it will be a part of the problem.

A default gateway route is only needed if there is another network
(LAN or Internet) attached to the eth0 LAN through X.X.10.1.  In that
case the laptop traffic will be sent to X.X.10.1 and that host must
receive LAN traffic bound for the laptop and ARP to find that that
traffic must be sent to the LAN's PPP host.  In short, if you don't
*know* that you need that default route then get rid of it.

If neither the above default route or the bogus yyyS0 is the problem then
the problem is likely with the laptop routing configuration.  With IP
forwarding and proxyarp, the "same subnet" configuration with no default
route to eth0 should work.

--

PPP-Q&A links, downloads:    http://users3.ev1.net/~ckite/public_html/
/* In my book, the first poster to resort to personal abuse in a Usenet
   debate loses by default.  -  Rod Smith */

 
 
 

ppp dialin server

Post by David Funnel » Thu, 23 May 2002 10:29:31


Aplogies for the ascii art

                                         Linux  PPP dialin
server                                          remote win98 laptop

-----------------------------|
|---------------------|
--------------------------|-ethO                  ppp0
|------------------------| X.X.11.2                |
LAN X.X.10.0                |X.X.10.240        X.X.11.1
|                                    |---------------------|
                                       --------------------------------

problem: from laptop I can ping ppp0, and eth0 but cannot ping hosts on LAN

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
X.X.11.2    *               255.255.255.255 UH    0      0        0 ppp0
X.X.10.0    *               255.255.255.0   U     0      0        0 eth0
127.0.0.0       *               255.0.0.0       U     0      0        0 lo
default         X.X.10.1    0.0.0.0         UG    0      0        0 eth0

X.X.10.1 is the LAN gatway to the internet
X.X.10.0 is class C private address

thanks again for your reply



> --- truncated ---

> > OPTION 1 SAME SUBNET
> > Give the ppp interface and remote computer addresses from the same subnet as
> > the rest of LAN (X.X.10.0)
> > In this case proxyarp needs to be working for packets to travel via the ppp
> > server.
> > I have put this option in
> > /etc/ppp/options.yyyS0
> > proxyarp

> > But when I manually check the arp table there are no entries. I tried manually
> > adding entries using the arp command but despite specifying a specific mac
> > address,  the arp entry would have a * character.

> > OPTION 2 DIFFERENT SUBNET
> > Give the ppp interface (X.X.11.1) and the remote computer (X.X.11.2) a
> > separate subnet.
> > My undestanding is that in this case I do not need proxyarp but the route
> > table to direct the traffic through the ppp server.
> > remote(X.X.11.2)  can ping server ppp (X.X.11.1) and also server eth0
> > (X.X.10.240) but nothing else on LAN

> > I am still learning about routing so any comments on this routing table would
> > be appreciated

> > Kernel IP routing table
> > Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
> > X.X.11.2    *               255.255.255.255 UH    0      0        0 ppp0
> > X.X.10.0    *               255.255.255.0   U     0      0        0 eth0
> > 127.0.0.0   *               255.0.0.0       U     0      0        0 lo
> > default         X.X.10.1    0.0.0.0         UG    0      0        0 eth0

> > cheers Dave

> ok this seems to be your configuration, right?

> +---------------+     +-------------------------+        +-------------+
> | server        |     | dial in server / router |        | laptop      |
> | X.X.10.240/24 |     | X.X.10.1/24 X.X.11.1/32 |        | X.X.11.2/32 |
> |     eth0      |     |  eth0           ppp0    |        |    ppp0     |
> +------+--------+     +---+--------------+------+        +-----+-------+
>         |    ethernet      |              |                     |
>      ---+------------------+---           +-------+             |
>                                                   /      ppp    |
>                                                  +--------------+

> you should be able to ping:
> 1. X.X.11.1 from the laptop, ok?
> 2. X.X.11.2 from the router, ok?
> 3. X.X.10.1 from the server, ok?
> 4. X.X.10.240 from the router, ok?

> now packets from X.X.10.1 to X.X.10.240 must be forwarded by the router
> machine
> the routing table says:
> -packets for network X.X.10 (line 2) shall be forwarded to interface eth0
> -packets for network X.X.11.2 (line 1, host route) should be forwarded
> to interface ppp0
> -anythink else (skip loopback) will be directed to eth0 (line 4, default
> route)this
> looks fine for me! this is how i would set it up anyway ...

> Now that you have to disclose the Xs in the addresses. If they are from
> a private pool(192.168 ... etc), IP does not have to forward them! see
> rfc??? (i forgot)

> --
> Kind Regards
>         Martin Daser
> -----

> -----
> "Technology is just another word for it doesn't work yet" - D. Adams

 
 
 

ppp dialin server

Post by David Funnel » Thu, 23 May 2002 10:40:26


My apolgies Clifford
Iin my posting I should have typed /etc/options/options.ttyS0

the contents of the file look like this
X.X.10.240:X.X.10.248
proxyarp

after the ppp connection is established I type the arp command and get the
following (ras is hostname of remote client)

Address                  HWtype  HWaddress           Flags Mask
Iface
ras                            *                 *
MP                  eth0

Should I be concerned that the mac address is an asterisk, i would have
expected to see the remote mac address
route table now looks like this

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
ras             *               255.255.255.255 UH    0      0        0 ppp0
X.X.10.0    *               255.255.255.0   U     0      0        0 eth0
127.0.0.0       *               255.0.0.0       U     0      0        0 lo



> > OPTION 1 SAME SUBNET
> > Give the ppp interface and remote computer addresses from the same
> > subnet as the rest of LAN (X.X.10.0) In this case proxyarp needs
> > to be working for packets to travel via the ppp server.

> Correct.

> > I have put this option in
> > /etc/ppp/options.yyyS0
> > proxyarp

> I hope you meant /etc/ppp/options.ttyS0 (and ttyS0 is the modem's device
> file), otherwise the yyyS0 is wrong and it certainly won't work...

> Providing the client with an IP address on the LAN's subnet is the easist
> way to go.  Using an IP address not on the LAN means that proxyarp won't
> work and you'll have to go to more trouble.

> > But when I manually check the arp table there are no entries. I tried
> > manually adding entries using the arp command but despite specifying
> > a specific mac address,  the arp entry would have a * character.

> It's been awhile since I set up a PPP host to accept calls, but the
> proxy arp tables for the Ethernet interface may not show any entries
> until a host on the LAN ARP's for the laptop IP address.

> You can use "tcpdump -i eth0" to see if there are any ARP requests
> being generated with a PPP connection.

> > Kernel IP routing table
> > Destination     Gateway         Genmask     Flags Metric Ref    Use Iface
> > X.X.11.2    *               255.255.255.255 UH    0      0        0 ppp0
> > X.X.10.0    *               255.255.255.0   U     0      0        0 eth0
> > 127.0.0.0       *           255.0.0.0       U     0      0        0 lo
> > default         X.X.10.1    0.0.0.0         UG    0      0        0 eth0

> This is for the case where the laptop has an IP address not on the LAN,
> which won't work without implementing routing on other hosts, or running
> a routing daemon on all LAN hosts, to make it happen.

> The default route shown above is not necessary for communication with
> the LAN and looks to me like it will be a part of the problem.

> A default gateway route is only needed if there is another network
> (LAN or Internet) attached to the eth0 LAN through X.X.10.1.  In that
> case the laptop traffic will be sent to X.X.10.1 and that host must
> receive LAN traffic bound for the laptop and ARP to find that that
> traffic must be sent to the LAN's PPP host.  In short, if you don't
> *know* that you need that default route then get rid of it.

> If neither the above default route or the bogus yyyS0 is the problem then
> the problem is likely with the laptop routing configuration.  With IP
> forwarding and proxyarp, the "same subnet" configuration with no default
> route to eth0 should work.

> --

> PPP-Q&A links, downloads:    http://users3.ev1.net/~ckite/public_html/
> /* In my book, the first poster to resort to personal abuse in a Usenet
>    debate loses by default.  -  Rod Smith */

 
 
 

ppp dialin server

Post by Clifford Kit » Thu, 23 May 2002 22:18:47



> Iin my posting I should have typed /etc/options/options.ttyS0
> the contents of the file look like this
> X.X.10.240:X.X.10.248
> proxyarp
> after the ppp connection is established I type the arp command and get the
> following (ras is hostname of remote client)
> Address                  HWtype  HWaddress           Flags Mask
> Iface
> ras                            *                 *
> MP                  eth0
> Should I be concerned that the mac address is an asterisk, i would have
> expected to see the remote mac address

That should not be a concern.  The PPP interface doesn't have a
MAC address and the MAC on the remote isn't used by any regular PPP
connection.  I don't know whether it is needed by PPP over Ethernet
(PPPoE) or not.  (Unfortunately, PPPoE is used by many ISPs for a DSL
connection.)

Quote:> route table now looks like this
> Kernel IP routing table
> Destination     Gateway     Genmask         Flags Metric Ref    Use Iface
> ras             *           255.255.255.255 UH    0      0        0 ppp0
> X.X.10.0    *               255.255.255.0   U     0      0        0 eth0
> 127.0.0.0       *           255.0.0.0       U     0      0        0 lo

It looks good, and the remote should now be able to access the LAN hosts.

--

PPP-Q&A links, downloads:    http://users3.ev1.net/~ckite/public_html/
/* Bluffing in a poker game can win big; bluffing in a newsgroup
   only attracts sharks. */

 
 
 

ppp dialin server

Post by David Funnel » Fri, 24 May 2002 11:59:56


It turned out that ip forwarding was not properly enabled. I was making
things more complicated than they needed to be by looking at arp and
route tables.

I had set
/etc/sysconfig/network
FORWARD_IPV4=true

apparently this did not work, when I tried

echo 1 > /proc/sys/net/ipv4/ip_forward

Everything worked.

Thanks again for the replies
David :-)



>>Iin my posting I should have typed /etc/options/options.ttyS0

>>the contents of the file look like this
>>X.X.10.240:X.X.10.248
>>proxyarp

>>after the ppp connection is established I type the arp command and get the
>>following (ras is hostname of remote client)

>>Address                  HWtype  HWaddress           Flags Mask
>>Iface
>>ras                            *                 *
>>MP                  eth0

>>Should I be concerned that the mac address is an asterisk, i would have
>>expected to see the remote mac address

> That should not be a concern.  The PPP interface doesn't have a
> MAC address and the MAC on the remote isn't used by any regular PPP
> connection.  I don't know whether it is needed by PPP over Ethernet
> (PPPoE) or not.  (Unfortunately, PPPoE is used by many ISPs for a DSL
> connection.)

>>route table now looks like this

>>Kernel IP routing table
>>Destination     Gateway     Genmask         Flags Metric Ref    Use Iface
>>ras             *           255.255.255.255 UH    0      0        0 ppp0
>>X.X.10.0    *               255.255.255.0   U     0      0        0 eth0
>>127.0.0.0       *           255.0.0.0       U     0      0        0 lo

> It looks good, and the remote should now be able to access the LAN hosts.

 
 
 

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