Re: [LARTC] ABout Routing..diag fixed..

Linux Advanced Routing and Traffic Control

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Not sure I can help, but I would try using 'traceroute' to see how far your packets travel.

My guess is that your have:

- A mal-formed routing table on the box using Masquerading. For a network like yours, consider using a dynamic routing deamon like 'gated' or 'routed', if you are having problems.

- You do not have packet-forwarding switched on. Look at the output of 'cat /proc/sys/net/ipv4/ip_forward'. Ensure it's set to '1'.

- Your iptables/ipchains do not have the forwarding chain is set to '-j ACCEPT' for the relevent connection. Check the default policy as well.

- Your iptables/ipchains are blocking you connection, which NAPT bypasses.

- Your netmasks are incorrect. I guess all your networks are sudo-Class-C? Ensure they are all set to '255.255.255.0' or '/24'.

Ben.



Dhirendra Pal Singh wrote:
Thanks to David and Martin,

Okay I am copying the diagram again.. I remade it in acsi and replaced the tabs with space.Have tested it on my box by sending the email to myself and another box. It looks fine..

I hope it dosent breaks this time



eth 0 192.168.1.50
\
|----------| \ |--------------|
-----------------| gateway 1|-------------------------|gateway2 |
/|_______ |\ |--------------|
/ \ / \
eth0 eth1 - / \
61.X.X.X 192.168.1.1 eth1 eth2
(public) | 192.168.2.51 192.168.3.52
| |
------------ |
| BOX 1 | -----------------
------------- | Box 3 |
192.168.1.101 ---------------
192.168.3.101
My Problem is


A) I am unable to ping from Box 3 (192.168.3.101) to Box 1(192.168.1.101). Any comments or reasons why?
B) I have figured out that if I enable Masquerading then problem A is solved. Can someone explain why?
C) Is it possible without Masquerading ?


I am in a fix and any Help would be very much appreciated...??

Thanks and Regards
Dp


Dhirendra Pal Singh wrote:


Hi All..
I think the image got screwed up...
I am giving the description again..

Dsl feed goes to gateway 1. Its internal ip address is of 192.168.1.XXX. Now from here goes the feed to another gateway which eth0 ip address is 192,168.1.50. It has 2 more eth - eth1 and eth2. Their ip address are 192.168.2.51 and 192.168.3.XXX respectively.
Now my problem is that all the computers connect to 192.168.2.XXX are unable to point to the computers of 192.168.1.XXX. Though strangely I can ping to 192.168.1.1 wich is the internal ip address of the gateway 1.


Can someone help me whith this configuration...?
rest question are below..
Thanks in advance ..
dp

Dhirendra Pal Singh wrote:

Hi All,
I have the following setup on redhat linux 8.0 ...

eth 0 192.168.1.50
\
|--------------| \ |--------------|
-----------------| gateway 1|-------------------------|gateway2 |
/|_______ |\ |--------------|
/ \ / \
eth0 eth1 - / \
61.X.X.X 192.168.1.1 eth1 eth2
(public) | 192.168.2.51 192.168.3.52
| |
------------ |
| BOX 1 | ---------------- ------------- | Box BOX 3 |
192.168.1.101 ---------------
192.168.3.101


My Problem is

A) I am unable to ping from Box 3 (192.168.3.101) to Box 1. Any comments or reasons why?
B) I have figured out that if I enable Masquerading then problem A is solved. Can someone explain why?
C) Is it possible without Masquerading ?


I am in a fix and any Help would be very much appreciated...??

Thanks and Regards
Dp



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