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ravi varma
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Capturing PPP packets with out port number
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ravi varma
11/06/2008 7:20 AM
post16061
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Capturing PPP packets with out port number
Hi
We have network consisting of three systems.
A - source
B - acting as router
C - destination
Between A-B we have UDP running over ethernet. Between B-C we need PPP over serail port.
Once ppp server and client are estbalished between B and C the IP address of C will be sent to A. which means all three
systems have defined IP, B will have 2 one on ehternet port and another for Serail port.
Now task is
1. when A trasmit packet with destiantion IP address of C, B should capture that and channel it through Serail port over
PPP protocol - for this we are planning to edit routing table of A so that for packets destianted toward C, B will act
as router. i.e from A the next hop for packets realted to C will be B - let me your comments
2. C is a third party system we dont have any control on it expect assignning IP, Initially we thought we will use
socket progamming to tranmsit and receive paskets between B and C, but we dont have any data of port number of C.
please let me know is there any way where i can capture raw packets destainted to an IP irrespective of port number.
simialrly how to send a packets to an Ip with out using scoket program and Port number.
thanks
Ravi
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Xiaodan Tang(deleted)
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Re: Capturing PPP packets with out port number
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Xiaodan Tang(deleted)
11/06/2008 7:46 AM
post16065
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Re: Capturing PPP packets with out port number
PPP already have this feature to help you, it called "proxyarp". :)
When B assign IP address to C, maker sure it assign an IP in same network of A and B. B also need "proxyarp" option for
it's PPPD command line.
It woks like this.
When A try to talk to C, since the IP is on same network, A will ARP. B will see this ARP, and even though it is not B's
IP, B will response. This way, A will send all it's C destination packet to B, B will then forward it.
Of cause you need to make sure forwarding is enabled on B.
-xtang
----- Original Message -----
From: ravi varma <community-noreply@qnx.com>
To: technology-networking <post16061@community.qnx.com>
Sent: Thu Nov 06 07:20:04 2008
Subject: Capturing PPP packets with out port number
Hi
We have network consisting of three systems.
A - source
B - acting as router
C - destination
Between A-B we have UDP running over ethernet. Between B-C we need PPP over serail port.
Once ppp server and client are estbalished between B and C the IP address of C will be sent to A. which means all three
systems have defined IP, B will have 2 one on ehternet port and another for Serail port.
Now task is
1. when A trasmit packet with destiantion IP address of C, B should capture that and channel it through Serail port over
PPP protocol - for this we are planning to edit routing table of A so that for packets destianted toward C, B will act
as router. i.e from A the next hop for packets realted to C will be B - let me your comments
2. C is a third party system we dont have any control on it expect assignning IP, Initially we thought we will use
socket progamming to tranmsit and receive paskets between B and C, but we dont have any data of port number of C.
please let me know is there any way where i can capture raw packets destainted to an IP irrespective of port number.
simialrly how to send a packets to an Ip with out using scoket program and Port number.
thanks
Ravi
_______________________________________________
Technology
http://community.qnx.com/sf/go/post16061
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ravi varma
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Re: Capturing PPP packets with out port number
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ravi varma
11/06/2008 9:35 AM
post16089
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Re: Capturing PPP packets with out port number
Hi Xtang
thanks for quick reponse, here is update for you
ip address of A : 192.168.0.51,B: 192.168.0.31, B: is running on VMware virtaul machine where card Ip is 192.168.0.11.
and on On B i executed follwoing command:
pppd/dev/ser1 proxyarp 115200 192.168.0.35:192.168.0.45
On C: pppd /dev/ser1 115200 ..after this B and C got IP'S confgiured for PPP. The rotuing table of B has follwoing
entries.
# route -v show
Routing tables
Internet:
Destination Gateway Flags
localhost.localdo 127.0.0.1 UH
192.168.0.0 link#2 U
192.168.0.11 00:80:ad:83:92:a6 UH
192.168.0.35 192.168.0.35 UH
192.168.0.45 192.168.0.35 UH
192.168.0.45 00:0c:29:ea:f4:a4 UH
after doing this i tried to ping from A to C - but it didnt happened, what i need to enable forwarding on B.
Also let me know
thanks
Ravi
> PPP already have this feature to help you, it called "proxyarp". :)
>
> When B assign IP address to C, maker sure it assign an IP in same network of A
> and B. B also need "proxyarp" option for it's PPPD command line.
>
> It woks like this.
>
> When A try to talk to C, since the IP is on same network, A will ARP. B will
> see this ARP, and even though it is not B's IP, B will response. This way, A
> will send all it's C destination packet to B, B will then forward it.
>
> Of cause you need to make sure forwarding is enabled on B.
>
> -xtang
>
> ----- Original Message -----
> From: ravi varma <community-noreply@qnx.com>
> To: technology-networking <post16061@community.qnx.com>
> Sent: Thu Nov 06 07:20:04 2008
> Subject: Capturing PPP packets with out port number
>
> Hi
>
> We have network consisting of three systems.
>
> A - source
> B - acting as router
> C - destination
>
> Between A-B we have UDP running over ethernet. Between B-C we need PPP over
> serail port.
>
> Once ppp server and client are estbalished between B and C the IP address of C
> will be sent to A. which means all three systems have defined IP, B will have
> 2 one on ehternet port and another for Serail port.
>
> Now task is
>
> 1. when A trasmit packet with destiantion IP address of C, B should capture
> that and channel it through Serail port over PPP protocol - for this we are
> planning to edit routing table of A so that for packets destianted toward C, B
> will act as router. i.e from A the next hop for packets realted to C will be
> B - let me your comments
>
> 2. C is a third party system we dont have any control on it expect assignning
> IP, Initially we thought we will use socket progamming to tranmsit and receive
> paskets between B and C, but we dont have any data of port number of C.
>
> please let me know is there any way where i can capture raw packets destainted
> to an IP irrespective of port number. simialrly how to send a packets to an
> Ip with out using scoket program and Port number.
>
>
> thanks
> Ravi
>
> _______________________________________________
> Technology
> http://community.qnx.com/sf/go/post16061
>
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Xiaodan Tang(deleted)
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RE: Capturing PPP packets with out port number
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Xiaodan Tang(deleted)
11/06/2008 9:48 AM
post16091
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RE: Capturing PPP packets with out port number
First, after failed to ping C, do a "arp -na" on A see if it find the
mac address of C (actually B). If not, we have problem in "proxyarp", we
need to fix this first.
If A do have C in its ARP entry, then:
The C need to be started as:
pppd /dev/ser1 115200 defaultroute
This way, C will always sent return packet to B.
For forwarding, try "sysctl -w net.inet.ip.forwarding=1".
-xtang
> -----Original Message-----
> From: ravi varma [mailto:community-noreply@qnx.com]
> Sent: Thursday, November 06, 2008 9:35 AM
> To: technology-networking
> Subject: Re: Capturing PPP packets with out port number
>
> Hi Xtang
>
> thanks for quick reponse, here is update for you ip address
> of A : 192.168.0.51,B: 192.168.0.31, B: is running on VMware
> virtaul machine where card Ip is 192.168.0.11.
>
> and on On B i executed follwoing command:
>
> pppd/dev/ser1 proxyarp 115200 192.168.0.35:192.168.0.45
>
> On C: pppd /dev/ser1 115200 ..after this B and C got IP'S
> confgiured for PPP. The rotuing table of B has follwoing entries.
>
> # route -v show
> Routing tables
>
> Internet:
> Destination Gateway Flags
> localhost.localdo 127.0.0.1 UH
> 192.168.0.0 link#2 U
> 192.168.0.11 00:80:ad:83:92:a6 UH
> 192.168.0.35 192.168.0.35 UH
> 192.168.0.45 192.168.0.35 UH
> 192.168.0.45 00:0c:29:ea:f4:a4 UH
>
> after doing this i tried to ping from A to C - but it didnt
> happened, what i need to enable forwarding on B.
>
> Also let me know
>
> thanks
> Ravi
>
> > PPP already have this feature to help you, it called "proxyarp". :)
> >
> > When B assign IP address to C, maker sure it assign an IP in same
> > network of A and B. B also need "proxyarp" option for it's
> PPPD command line.
> >
> > It woks like this.
> >
> > When A try to talk to C, since the IP is on same network, A
> will ARP.
> > B will see this ARP, and even though it is not B's IP, B will
> > response. This way, A will send all it's C destination
> packet to B, B will then forward it.
> >
> > Of cause you need to make sure forwarding is enabled on B.
> >
> > -xtang
> >
> > ----- Original Message -----
> > From: ravi varma <community-noreply@qnx.com>
> > To: technology-networking <post16061@community.qnx.com>
> > Sent: Thu Nov 06 07:20:04 2008
> > Subject: Capturing PPP packets with out port number
> >
> > Hi
> >
> > We have network consisting of three systems.
> >
> > A - source
> > B - acting as router
> > C - destination
> >
> > Between A-B we have UDP running over ethernet. Between B-C
> we need PPP
> > over serail port.
> >
> > Once ppp server and client are estbalished between B and C the IP
> > address of C will be sent to A. which means all three systems have
> > defined IP, B will have
> > 2 one on ehternet port and another for Serail port.
> >
> > Now task is
> >
> > 1. when A trasmit packet with destiantion IP address of C, B should
> > capture that and channel it through Serail port over PPP protocol -
> > for this we are planning to edit routing table of A so that for
> > packets destianted toward C, B will act as router. i.e from A the
> > next hop for packets realted to C will be B - let me your comments
> >
> > 2. C is a third party system we dont have any control on it expect
> > assignning IP, Initially we thought we will use socket
> progamming to
> > tranmsit and receive paskets between B and C, but we dont...
View Full Message
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ravi varma
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Re: RE: Capturing PPP packets with out port number
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ravi varma
11/07/2008 6:39 AM
post16161
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Re: RE: Capturing PPP packets with out port number
Hi Xtang
thanks for your comment. Its working now i am able to ping from A to C. By doing arp -na i am able to see mac adddrss of
B for both ip's.
192.168.0.31
192.168.0.45 ...
Coming on to my second question in actual system configuration C is a third party system we dont have any control on it
expect assignning IP,
Normally i use socket program to send and receive packets from/to Ip which need specific port number.
Since we made default route in C as PPP, i can think that C might accept packet when send with any port number. But how
cna i receive packet from C with a scoket program running in A, i dont have any clue of which port number to attach to
socket.
thanks
Ravi
> First, after failed to ping C, do a "arp -na" on A see if it find the
> mac address of C (actually B). If not, we have problem in "proxyarp", we
> need to fix this first.
>
> If A do have C in its ARP entry, then:
>
> The C need to be started as:
>
> pppd /dev/ser1 115200 defaultroute
>
> This way, C will always sent return packet to B.
>
> For forwarding, try "sysctl -w net.inet.ip.forwarding=1".
>
> -xtang
>
> > -----Original Message-----
> > From: ravi varma [mailto:community-noreply@qnx.com]
> > Sent: Thursday, November 06, 2008 9:35 AM
> > To: technology-networking
> > Subject: Re: Capturing PPP packets with out port number
> >
> > Hi Xtang
> >
> > thanks for quick reponse, here is update for you ip address
> > of A : 192.168.0.51,B: 192.168.0.31, B: is running on VMware
> > virtaul machine where card Ip is 192.168.0.11.
> >
> > and on On B i executed follwoing command:
> >
> > pppd/dev/ser1 proxyarp 115200 192.168.0.35:192.168.0.45
> >
> > On C: pppd /dev/ser1 115200 ..after this B and C got IP'S
> > confgiured for PPP. The rotuing table of B has follwoing entries.
> >
> > # route -v show
> > Routing tables
> >
> > Internet:
> > Destination Gateway Flags
> > localhost.localdo 127.0.0.1 UH
> > 192.168.0.0 link#2 U
> > 192.168.0.11 00:80:ad:83:92:a6 UH
> > 192.168.0.35 192.168.0.35 UH
> > 192.168.0.45 192.168.0.35 UH
> > 192.168.0.45 00:0c:29:ea:f4:a4 UH
> >
> > after doing this i tried to ping from A to C - but it didnt
> > happened, what i need to enable forwarding on B.
> >
> > Also let me know
> >
> > thanks
> > Ravi
> >
> > > PPP already have this feature to help you, it called "proxyarp". :)
> > >
> > > When B assign IP address to C, maker sure it assign an IP in same
> > > network of A and B. B also need "proxyarp" option for it's
> > PPPD command line.
> > >
> > > It woks like this.
> > >
> > > When A try to talk to C, since the IP is on same network, A
> > will ARP.
> > > B will see this ARP, and even though it is not B's IP, B will
> > > response. This way, A will send all it's C destination
> > packet to B, B will then forward it.
> > >
> > > Of cause you need to make sure forwarding is enabled on B.
> > >
> > > -xtang
> > >
> > > ----- Original Message -----
> > > From: ravi varma <community-noreply@qnx.com>
> > > To: technology-networking <post16061@community.qnx.com>
> > > Sent: Thu Nov 06 07:20:04 2008
> > > Subject: Capturing PPP packets with out port number
> > >
> > > Hi
> > >
> > > We have network consisting of three systems.
> > >
> > > A - source
> >...
View Full Message
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Xiaodan Tang(deleted)
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RE: RE: Capturing PPP packets with out port number
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Xiaodan Tang(deleted)
11/07/2008 11:15 AM
post16210
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RE: RE: Capturing PPP packets with out port number
Hi Ravi,
I am not sure I follow you.
"port number" is a UDP/TCP thing, "routing" is an IP thing.
By setting "defaultroute" on C, you tell C that "to reach A (or to reach
anybody), send the packet to B". So when you ping, telnet, ... from A
to C, the "return packet" that C want to send back to A, will all goes
to B. And of cause, B knows how to route it back to A.
"defaultroute" is a very normal option on ppp. Because from C's point of
view, B is his only way to get to internet.
If you really don't have any control of C, and C is not setting up any
proper routing table to allow A to access it. You have other options:
1) If both A and B are QNX, then there is QNET
2) if only B is QNX, then you need NAT (network address translate).
Regards,
-xtang
> -----Original Message-----
> From: ravi varma [mailto:community-noreply@qnx.com]
> Sent: Friday, November 07, 2008 6:40 AM
> To: technology-networking
> Subject: Re: RE: Capturing PPP packets with out port number
>
> Hi Xtang
>
> thanks for your comment. Its working now i am able to ping
> from A to C. By doing arp -na i am able to see mac adddrss of
> B for both ip's.
>
> 192.168.0.31
> 192.168.0.45 ...
>
> Coming on to my second question in actual system
> configuration C is a third party system we dont have any
> control on it expect assignning IP,
>
> Normally i use socket program to send and receive packets
> from/to Ip which need specific port number.
>
> Since we made default route in C as PPP, i can think that C
> might accept packet when send with any port number. But how
> cna i receive packet from C with a scoket program running in
> A, i dont have any clue of which port number to attach to socket.
>
> thanks
> Ravi
>
>
>
>
>
> > First, after failed to ping C, do a "arp -na" on A see if
> it find the
> > mac address of C (actually B). If not, we have problem in
> "proxyarp", we
> > need to fix this first.
> >
> > If A do have C in its ARP entry, then:
> >
> > The C need to be started as:
> >
> > pppd /dev/ser1 115200 defaultroute
> >
> > This way, C will always sent return packet to B.
> >
> > For forwarding, try "sysctl -w net.inet.ip.forwarding=1".
> >
> > -xtang
> >
> > > -----Original Message-----
> > > From: ravi varma [mailto:community-noreply@qnx.com]
> > > Sent: Thursday, November 06, 2008 9:35 AM
> > > To: technology-networking
> > > Subject: Re: Capturing PPP packets with out port number
> > >
> > > Hi Xtang
> > >
> > > thanks for quick reponse, here is update for you ip address
> > > of A : 192.168.0.51,B: 192.168.0.31, B: is running on VMware
> > > virtaul machine where card Ip is 192.168.0.11.
> > >
> > > and on On B i executed follwoing command:
> > >
> > > pppd/dev/ser1 proxyarp 115200 192.168.0.35:192.168.0.45
> > >
> > > On C: pppd /dev/ser1 115200 ..after this B and C got IP'S
> > > confgiured for PPP. The rotuing table of B has follwoing entries.
> > >
> > > # route -v show
> > > Routing tables
> > >
> > > Internet:
> > > Destination Gateway Flags
> > > localhost.localdo 127.0.0.1 UH
> > > 192.168.0.0 link#2 U
> > > 192.168.0.11 00:80:ad:83:92:a6 UH
> > > 192.168.0.35 192.168.0.35 UH
> > > 192.168.0.45 192.168.0.35 UH
> > > 192.168.0.45 00:0c:29:ea:f4:a4 UH
> > >
> > > after doing this i tried to ping from A to C - but it didnt...
View Full Message
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ravi varma
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Re: RE: RE: Capturing PPP packets with out port number
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ravi varma
11/10/2008 2:02 AM
post16285
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Re: RE: RE: Capturing PPP packets with out port number
Hi
Sorry if it confused you, what i am aksing is from program point of view.
See A will be sending messages some of which are specific to B and some are specific to C. So i will enable forwarding
in B so that all messages related to C will be forwarded to C.
My question is : Now from A point of view if i need to receive or transmit messages to C through a socket program, how
can i do that with out knowing port number of C. Since in socket program we require port number to sent or receive UDP
frames.
Is there any approcah to send/Receive packets at raw level where Port number will not come into picture.
Thanks
Ravi
> Hi Ravi,
>
> I am not sure I follow you.
>
> "port number" is a UDP/TCP thing, "routing" is an IP thing.
>
> By setting "defaultroute" on C, you tell C that "to reach A (or to reach
> anybody), send the packet to B". So when you ping, telnet, ... from A
> to C, the "return packet" that C want to send back to A, will all goes
> to B. And of cause, B knows how to route it back to A.
>
> "defaultroute" is a very normal option on ppp. Because from C's point of
> view, B is his only way to get to internet.
>
> If you really don't have any control of C, and C is not setting up any
> proper routing table to allow A to access it. You have other options:
>
> 1) If both A and B are QNX, then there is QNET
>
> 2) if only B is QNX, then you need NAT (network address translate).
>
> Regards,
> -xtang
>
> > -----Original Message-----
> > From: ravi varma [mailto:community-noreply@qnx.com]
> > Sent: Friday, November 07, 2008 6:40 AM
> > To: technology-networking
> > Subject: Re: RE: Capturing PPP packets with out port number
> >
> > Hi Xtang
> >
> > thanks for your comment. Its working now i am able to ping
> > from A to C. By doing arp -na i am able to see mac adddrss of
> > B for both ip's.
> >
> > 192.168.0.31
> > 192.168.0.45 ...
> >
> > Coming on to my second question in actual system
> > configuration C is a third party system we dont have any
> > control on it expect assignning IP,
> >
> > Normally i use socket program to send and receive packets
> > from/to Ip which need specific port number.
> >
> > Since we made default route in C as PPP, i can think that C
> > might accept packet when send with any port number. But how
> > cna i receive packet from C with a scoket program running in
> > A, i dont have any clue of which port number to attach to socket.
> >
> > thanks
> > Ravi
> >
> >
> >
> >
> >
> > > First, after failed to ping C, do a "arp -na" on A see if
> > it find the
> > > mac address of C (actually B). If not, we have problem in
> > "proxyarp", we
> > > need to fix this first.
> > >
> > > If A do have C in its ARP entry, then:
> > >
> > > The C need to be started as:
> > >
> > > pppd /dev/ser1 115200 defaultroute
> > >
> > > This way, C will always sent return packet to B.
> > >
> > > For forwarding, try "sysctl -w net.inet.ip.forwarding=1".
> > >
> > > -xtang
> > >
> > > > -----Original Message-----
> > > > From: ravi varma [mailto:community-noreply@qnx.com]
> > > > Sent: Thursday, November 06, 2008 9:35 AM
> > > > To: technology-networking
> > > > Subject: Re: Capturing PPP packets with out port number
> > > >
> > > > Hi Xtang
> > > >
> > > > thanks for quick reponse, here is update for you ip address
> > > >...
View Full Message
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Robert Craig
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RE: RE: RE: Capturing PPP packets with out port number
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Robert Craig
11/10/2008 9:59 AM
post16306
|
RE: RE: RE: Capturing PPP packets with out port number
I think that you're asking a very different question here. This is
solely at the application level and is at your discretion. The "normal"
mechanism for doing this is to use a "well known" port for your service
(that is, you pick a port that both the server and client use). You
could use raw IP but that bypasses all of the advantages of using the
higher layer protocols.
R.
-----Original Message-----
From: ravi varma [mailto:community-noreply@qnx.com]
Sent: Monday, November 10, 2008 2:02 AM
To: technology-networking
Subject: Re: RE: RE: Capturing PPP packets with out port number
Hi
Sorry if it confused you, what i am aksing is from program point of
view.
See A will be sending messages some of which are specific to B and some
are specific to C. So i will enable forwarding in B so that all messages
related to C will be forwarded to C.
My question is : Now from A point of view if i need to receive or
transmit messages to C through a socket program, how can i do that with
out knowing port number of C. Since in socket program we require port
number to sent or receive UDP frames.
Is there any approcah to send/Receive packets at raw level where Port
number will not come into picture.
Thanks
Ravi
> Hi Ravi,
>
> I am not sure I follow you.
>
> "port number" is a UDP/TCP thing, "routing" is an IP thing.
>
> By setting "defaultroute" on C, you tell C that "to reach A (or to
reach
> anybody), send the packet to B". So when you ping, telnet, ... from A
> to C, the "return packet" that C want to send back to A, will all
goes
> to B. And of cause, B knows how to route it back to A.
>
> "defaultroute" is a very normal option on ppp. Because from C's point
of
> view, B is his only way to get to internet.
>
> If you really don't have any control of C, and C is not setting up any
> proper routing table to allow A to access it. You have other options:
>
> 1) If both A and B are QNX, then there is QNET
>
> 2) if only B is QNX, then you need NAT (network address translate).
>
> Regards,
> -xtang
>
> > -----Original Message-----
> > From: ravi varma [mailto:community-noreply@qnx.com]
> > Sent: Friday, November 07, 2008 6:40 AM
> > To: technology-networking
> > Subject: Re: RE: Capturing PPP packets with out port number
> >
> > Hi Xtang
> >
> > thanks for your comment. Its working now i am able to ping
> > from A to C. By doing arp -na i am able to see mac adddrss of
> > B for both ip's.
> >
> > 192.168.0.31
> > 192.168.0.45 ...
> >
> > Coming on to my second question in actual system
> > configuration C is a third party system we dont have any
> > control on it expect assignning IP,
> >
> > Normally i use socket program to send and receive packets
> > from/to Ip which need specific port number.
> >
> > Since we made default route in C as PPP, i can think that C
> > might accept packet when send with any port number. But how
> > cna i receive packet from C with a scoket program running in
> > A, i dont have any clue of which port number to attach to socket.
> >
> > thanks
> > Ravi
> >
> >
> >
> >
> >
> > > First, after failed to ping C, do a "arp -na" on A see if
> > it find the
> > > mac address of C (actually B). If not, we have problem in
> > "proxyarp", we
> > > need to fix this first.
> > >
> > > If A do have C in its ARP entry, then:
> > >
> > > The C need to be started as:
> > >
> > > pppd /dev/ser1 115200 defaultroute
> > >
> > > This way, C will always sent return packet to B.
> > >...
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ravi varma
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Re: RE: RE: RE: Capturing PPP packets with out port number
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ravi varma
11/11/2008 6:28 AM
post16370
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Re: RE: RE: RE: Capturing PPP packets with out port number
Hi
thanks, i got the solution. since B is transparently passing messages among A and C, this is fine for me. of late i came
to know that vendor will support sofware in A which will communciate with C, so internally they might be fixing the
port number to be same on both sides.
Thnaks for your support.
Ravi
> I think that you're asking a very different question here. This is
> solely at the application level and is at your discretion. The "normal"
> mechanism for doing this is to use a "well known" port for your service
> (that is, you pick a port that both the server and client use). You
> could use raw IP but that bypasses all of the advantages of using the
> higher layer protocols.
>
> R.
>
>
> -----Original Message-----
> From: ravi varma [mailto:community-noreply@qnx.com]
> Sent: Monday, November 10, 2008 2:02 AM
> To: technology-networking
> Subject: Re: RE: RE: Capturing PPP packets with out port number
>
> Hi
>
> Sorry if it confused you, what i am aksing is from program point of
> view.
> See A will be sending messages some of which are specific to B and some
> are specific to C. So i will enable forwarding in B so that all messages
> related to C will be forwarded to C.
>
> My question is : Now from A point of view if i need to receive or
> transmit messages to C through a socket program, how can i do that with
> out knowing port number of C. Since in socket program we require port
> number to sent or receive UDP frames.
>
> Is there any approcah to send/Receive packets at raw level where Port
> number will not come into picture.
>
> Thanks
> Ravi
>
> > Hi Ravi,
> >
> > I am not sure I follow you.
> >
> > "port number" is a UDP/TCP thing, "routing" is an IP thing.
> >
> > By setting "defaultroute" on C, you tell C that "to reach A (or to
> reach
> > anybody), send the packet to B". So when you ping, telnet, ... from A
> > to C, the "return packet" that C want to send back to A, will all
> goes
> > to B. And of cause, B knows how to route it back to A.
> >
> > "defaultroute" is a very normal option on ppp. Because from C's point
> of
> > view, B is his only way to get to internet.
> >
> > If you really don't have any control of C, and C is not setting up any
> > proper routing table to allow A to access it. You have other options:
> >
> > 1) If both A and B are QNX, then there is QNET
> >
> > 2) if only B is QNX, then you need NAT (network address translate).
> >
> > Regards,
> > -xtang
> >
> > > -----Original Message-----
> > > From: ravi varma [mailto:community-noreply@qnx.com]
> > > Sent: Friday, November 07, 2008 6:40 AM
> > > To: technology-networking
> > > Subject: Re: RE: Capturing PPP packets with out port number
> > >
> > > Hi Xtang
> > >
> > > thanks for your comment. Its working now i am able to ping
> > > from A to C. By doing arp -na i am able to see mac adddrss of
> > > B for both ip's.
> > >
> > > 192.168.0.31
> > > 192.168.0.45 ...
> > >
> > > Coming on to my second question in actual system
> > > configuration C is a third party system we dont have any
> > > control on it expect assignning IP,
> > >
> > > Normally i use socket program to send and receive packets
> > > from/to Ip which need specific port number.
> > >
> > > Since we made default route in C as PPP, i can think that C
> > > might accept packet when send with any port number. But how
> > > cna i receive packet from C...
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ravi varma
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Re: RE: RE: RE: Capturing PPP packets with out port number
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ravi varma
12/01/2008 8:11 AM
post17619
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Re: RE: RE: RE: Capturing PPP packets with out port number
Hi
i am facing probelm with port forwarding. As discussed in earlier post
We have network consisting of three systems. A - source, B - acting as router, C - destination.
A ip: 192.168.0.31, B IP:192.168.0.51
Between A-B we have UDP running over ethernet. Between B-C
we need PPP over serail port. i used
pppd/dev/ser1 proxyarp 115200 192.168.0.61:192.168.0.62 between B and C. and on C :
pppd/dev/ser1 proxyarp 115200 defaultroute
and i also enabled port forwarding by sysctl -w net.inet.ip.forwarding=1
Earlier i was able to do ftp from A to C, but suddenly i am not sure what happened i am not even able to ping from A to
C, when i checked
arp -na on A i am able to see entry of C as
? (192.168.0.62) ar 00:12:3f:2d:31:2c on en0 ... the MAc addr shown is that of B's ethernet port, which is hope is
correct.
route table in B has entry
dest Gateway flags
192.168.0.65 00:12:3f:2d:31:2c UH
it is same MAC addr of ethernet port.
I also observed by doing ping -r 192.168.0.62 from A for which i am getting:
36 bytes from 192.168.0.51: Time to Live exceeded for icmp_seq=0..
which is making me to think that forwarding is done properly... is there any thing that i need to do ?, or any other way
.
i tried traceroute etc but it was abel to trace from A tol B, moreover i am not sure it is applicale to ppp over serial
link.
thanks
Ravi
> > > > > > >
> > > > > > > Once ppp server and client are estbalished between B
> > > > and C the IP
> > > > > > > address of C will be sent to A. which means all three
> > > > systems have
> > > > > > > defined IP, B will have
> > > > > > > 2 one on ehternet port and another for Serail port.
> > > > > > >
> > > > > > > Now task is
> Hi
>
> thanks, i got the solution. since B is transparently passing messages among A
> and C, this is fine for me. of late i came to know that vendor will support
> sofware in A which will communciate with C, so internally they might be fixing
> the port number to be same on both sides.
>
> Thnaks for your support.
>
> Ravi
>
> > I think that you're asking a very different question here. This is
> > solely at the application level and is at your discretion. The "normal"
> > mechanism for doing this is to use a "well known" port for your service
> > (that is, you pick a port that both the server and client use). You
> > could use raw IP but that bypasses all of the advantages of using the
> > higher layer protocols.
> >
> > R.
> >
> >
> > -----Original Message-----
> > From: ravi varma [mailto:community-noreply@qnx.com]
> > Sent: Monday, November 10, 2008 2:02 AM
> > To: technology-networking
> > Subject: Re: RE: RE: Capturing PPP packets with out port number
> >
> > Hi
> >
> > Sorry if it confused you, what i am aksing is from program point of
> > view.
> > See A will be sending messages some of which are specific to B and some
> > are specific to C. So i will enable forwarding in B so that all messages
> > related to C will be forwarded to C.
> >
> > My question is : Now from A point of view if i need to receive or
> > transmit messages to C through a socket program, how can i do that with
> > out knowing port number of C. Since in socket program we require port
> > number to sent or receive UDP frames.
> >
> > Is there any approcah to send/Receive packets at raw level where Port
> > number will not come into picture.
> >
> > Thanks
> > Ravi
> >
> > > Hi Ravi,
> >...
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Robert Craig
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RE: RE: RE: RE: Capturing PPP packets with out port number
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Robert Craig
12/01/2008 11:34 AM
post17647
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RE: RE: RE: RE: Capturing PPP packets with out port number
What do you're routing tables look like for each host?
(route show)
Robert.
-----Original Message-----
From: ravi varma [mailto:community-noreply@qnx.com]
Sent: Monday, December 01, 2008 8:11 AM
To: technology-networking
Subject: Re: RE: RE: RE: Capturing PPP packets with out port number
Hi
i am facing probelm with port forwarding. As discussed in earlier post
We have network consisting of three systems. A - source, B - acting as
router, C - destination.
A ip: 192.168.0.31, B IP:192.168.0.51
Between A-B we have UDP running over ethernet. Between B-C we need PPP
over serail port. i used
pppd/dev/ser1 proxyarp 115200 192.168.0.61:192.168.0.62 between B and C.
and on C :
pppd/dev/ser1 proxyarp 115200 defaultroute
and i also enabled port forwarding by sysctl -w net.inet.ip.forwarding=1
Earlier i was able to do ftp from A to C, but suddenly i am not sure
what happened i am not even able to ping from A to C, when i checked arp
-na on A i am able to see entry of C as
? (192.168.0.62) ar 00:12:3f:2d:31:2c on en0 ... the MAc addr shown is
that of B's ethernet port, which is hope is correct.
route table in B has entry
dest Gateway flags
192.168.0.65 00:12:3f:2d:31:2c UH
it is same MAC addr of ethernet port.
I also observed by doing ping -r 192.168.0.62 from A for which i am
getting:
36 bytes from 192.168.0.51: Time to Live exceeded for icmp_seq=0..
which is making me to think that forwarding is done properly... is there
any thing that i need to do ?, or any other way.
i tried traceroute etc but it was abel to trace from A tol B, moreover i
am not sure it is applicale to ppp over serial link.
thanks
Ravi
> > > > > > >
> > > > > > > Once ppp server and client are estbalished between B
> > > > and C the IP
> > > > > > > address of C will be sent to A. which means all three
> > > > systems have
> > > > > > > defined IP, B will have
> > > > > > > 2 one on ehternet port and another for Serail port.
> > > > > > >
> > > > > > > Now task is
> Hi
>
> thanks, i got the solution. since B is transparently passing messages
> among A and C, this is fine for me. of late i came to know that vendor
> will support sofware in A which will communciate with C, so internally
> they might be fixing the port number to be same on both sides.
>
> Thnaks for your support.
>
> Ravi
>
> > I think that you're asking a very different question here. This is
> > solely at the application level and is at your discretion. The
"normal"
> > mechanism for doing this is to use a "well known" port for your
> > service (that is, you pick a port that both the server and client
> > use). You could use raw IP but that bypasses all of the advantages
> > of using the higher layer protocols.
> >
> > R.
> >
> >
> > -----Original Message-----
> > From: ravi varma [mailto:community-noreply@qnx.com]
> > Sent: Monday, November 10, 2008 2:02 AM
> > To: technology-networking
> > Subject: Re: RE: RE: Capturing PPP packets with out port number
> >
> > Hi
> >
> > Sorry if it confused you, what i am aksing is from program point of
> > view.
> > See A will be sending messages some of which are specific to B and
> > some are specific to C. So i will enable forwarding in B so that all
> > messages related to C will be forwarded to C.
> >
> > My question is : Now from A point of view if i need to receive or
> > transmit messages to C through a socket program, how can i do that
> > with out knowing port number of C. Since in...
View Full Message
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Xiaodan Tang(deleted)
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Re: RE: RE: RE: Capturing PPP packets with out port number
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Xiaodan Tang(deleted)
12/01/2008 11:45 AM
post17649
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Re: RE: RE: RE: Capturing PPP packets with out port number
Can you "ping -n 192.168.0.62" from B ?
C is standalone, and do not have other Ethernet connection does it?
To find out the detail, we probably need "netstat -ni" and "netstat -nr" output from all 3 machines.
-xtang
> Hi
>
> i am facing probelm with port forwarding. As discussed in earlier post
>
> We have network consisting of three systems. A - source, B - acting as router,
> C - destination.
>
> A ip: 192.168.0.31, B IP:192.168.0.51
>
> Between A-B we have UDP running over ethernet. Between B-C
> we need PPP over serail port. i used
> pppd/dev/ser1 proxyarp 115200 192.168.0.61:192.168.0.62 between B and C. and
> on C :
> pppd/dev/ser1 proxyarp 115200 defaultroute
>
> and i also enabled port forwarding by sysctl -w net.inet.ip.forwarding=1
> Earlier i was able to do ftp from A to C, but suddenly i am not sure what
> happened i am not even able to ping from A to C, when i checked
> arp -na on A i am able to see entry of C as
>
> ? (192.168.0.62) ar 00:12:3f:2d:31:2c on en0 ... the MAc addr shown is that of
> B's ethernet port, which is hope is correct.
>
> route table in B has entry
>
> dest Gateway flags
> 192.168.0.65 00:12:3f:2d:31:2c UH
>
> it is same MAC addr of ethernet port.
>
> I also observed by doing ping -r 192.168.0.62 from A for which i am getting:
>
> 36 bytes from 192.168.0.51: Time to Live exceeded for icmp_seq=0..
> which is making me to think that forwarding is done properly... is there any
> thing that i need to do ?, or any other way.
>
> i tried traceroute etc but it was abel to trace from A tol B, moreover i am
> not sure it is applicale to ppp over serial link.
>
> thanks
> Ravi
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ravi varma
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Re: RE: RE: RE: Capturing PPP packets with out port number
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ravi varma
12/03/2008 2:42 AM
post17820
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Re: RE: RE: RE: Capturing PPP packets with out port number
Hi
I added new route in routing table of C, i observed even though i am enabling C as pppd/dev/ser1 proxyarp 115200
defaultroute the default route chosen is for some other ip address than A, so i added new route
route add ipA ipb , ip b is ip of serail port ruuning on PPP..it is working now..but thanks for suggesting "netstat -ni
" and "netstat -nr" they were helpful in debugging
Thanks
Ravi
> Can you "ping -n 192.168.0.62" from B ?
>
> C is standalone, and do not have other Ethernet connection does it?
>
> To find out the detail, we probably need "netstat -ni" and "netstat -nr"
> output from all 3 machines.
>
> -xtang
>
> > Hi
> >
> > i am facing probelm with port forwarding. As discussed in earlier post
> >
> > We have network consisting of three systems. A - source, B - acting as
> router,
> > C - destination.
> >
> > A ip: 192.168.0.31, B IP:192.168.0.51
> >
> > Between A-B we have UDP running over ethernet. Between B-C
> > we need PPP over serail port. i used
> > pppd/dev/ser1 proxyarp 115200 192.168.0.61:192.168.0.62 between B and C. and
>
> > on C :
> > pppd/dev/ser1 proxyarp 115200 defaultroute
> >
> > and i also enabled port forwarding by sysctl -w net.inet.ip.forwarding=1
> > Earlier i was able to do ftp from A to C, but suddenly i am not sure what
> > happened i am not even able to ping from A to C, when i checked
> > arp -na on A i am able to see entry of C as
> >
> > ? (192.168.0.62) ar 00:12:3f:2d:31:2c on en0 ... the MAc addr shown is that
> of
> > B's ethernet port, which is hope is correct.
> >
> > route table in B has entry
> >
> > dest Gateway flags
> > 192.168.0.65 00:12:3f:2d:31:2c UH
> >
> > it is same MAC addr of ethernet port.
> >
> > I also observed by doing ping -r 192.168.0.62 from A for which i am getting:
>
> >
> > 36 bytes from 192.168.0.51: Time to Live exceeded for icmp_seq=0..
> > which is making me to think that forwarding is done properly... is there any
>
> > thing that i need to do ?, or any other way.
> >
> > i tried traceroute etc but it was abel to trace from A tol B, moreover i am
>
> > not sure it is applicale to ppp over serial link.
> >
> > thanks
> > Ravi
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