[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: subnetting help



On Tuesday 18 March 2003, at 22 h 24, 
Stephane Bortzmeyer <bortzmeyer at gitoyen.net> wrote:

> I must confess I cannot make head nor tail from it. Can you draw a nice ASCII
> diagram of your network? With the *names* (names are necessary for 
> communication)
> of the machines and the links between them?

Here is an example of a (IMHO) proper way to describe a network. I do not know 
how close it is from yours, because you provide very few details and it is 
often confusing.

1) You draw the network.

   TO THE INTERNET
 +--------------------+		   Management network 64.110.88.0/28
 |SuperNet	      |		--------+------
 |(upstream provider) |		  	|      
 +--------------------+	       	     	|      
       	 |     	      		     	|      
	 | Serial0		     	| eth1 (.1)  
 +---------------+	       	+----------------+   		   
 | nelson 	 |		|    steve     	 |   		   
 |(cisco router) |		| (linux router) |   		   
 +---------------+     	       	+----------------+     	      	   
    / |	 | Ethernet0 (.65)     	     	| eth0 	(.68)	      	   
   /  |	 +----------------------------------------------      
  /   |	 			     Backbone  64.110.88.64/26
 PtP links     	       	       	       	       		      
to customers						      
 64.110.88.32/27					      
							      
							      
2) You give the actual configuration (not a summary, not a translation)


! nelson, cisco router
ip subnet-zero
ip classless
interface Ethernet0  
  ! /26
  ip address 64.110.88.65 netmask 255.255.255.192
interface Serial0
  ip unnumbered Ethernet0
! Interfaces to PtP customers omitted
ip route 64.110.88.88 255.255.255.240 64.110.88.68 

# steve, Linux router
ifconfig eth0 64.110.88.68 netmask 255.255.255.192 # /26
ifconfig eth1 64.110.88.1 netmask 255.255.255.240 # /28
route add -net 64.110.88.32/27 gw 64.110.88.65
route add default gw 64.110.88.65

3) You can ask your question, with actual facts (output of commands, copy of 
log files, not vague interpretations)

From steve, I can get to the PtP customers and to any machine in my network. 
But why can't I reach the Internet from steve? I get:

~ % traceroute www.google.com
traceroute to www.google.com (216.239.39.104), 30 hops max, 38 byte packets
 1  nelson.example.com (64.110.88.65)  1.864 ms  1.689 ms  1.334 ms
 2  nelson.example.com (64.110.88.65) 1.443 ms !N  1.403 ms !N  1.173 ms !N

4) And you get a reply. (There is no default route on nelson, add "ip route 
0.0.0.0 0.0.0.0 Serial0")








-----
This is the afnog mailing list, managed by Majordomo 1.94.5

To send a message to this list, e-mail afnog at afnog.org
To send a request to majordomo, e-mail majordomo at afnog.org and put
your request in the body of the message (i.e use "help" for help)

This list is maintained by owner-afnog at afnog.org