ITEM: BJ8586L
Using PPP and Proxy arp
Question:
DESCRIPTION: How do you set up proxy arp for PPP.
Response:
Using Proxy ARP with a PPP Connection
Objective
When a user dials into a network, it is sometimes usefull to have the user
become a part of the local subnet. This can be accomplished with a proxy
arp, and by setting up the local address of the PPP server at the same
address of the network interface. For example:
* System One has a token ring address of 9.19.129.12.
* The Subnet for the system is 255.255.255.0
* The hardware address for System One is: 10.0.5a.a8.84.9d
* The Desired remote (dial in) system address is 9.19.130.184.
Steps
For more detail on creating a server, see the PPP cookbook.
1. Add the PPP Link for the server.
o smit ppp
o Link Control Configuration
o Add a Link Configuration
o Fill at least the following fields:
+ PPP subsystem name: Unique name up to 25 chars
+ max server connections: At least 1.
+ max client connections: 0 for server, unless also a client.
+ max ip interfaces: At least 1, (Server + client)
+ max async hdlc attachments: At least 1, Number of active
connections
o Hit enter to add Link
2. Add the PPP IP server address.
o smit ppp
o PPP IP Interfaces
o Add a Server Interface
o FIll in the following fields:
+ Local IP address: Make this the same as your token ring
address.
Example: 9.19.129.12
+ Staring Remote IP address: Desired remote address.
Example: 9.19.130.184
+ Number of addresses: At least one, For example use 1.
+ Netmask: Use netmask of local subnet
Example: 255.255.240.0
o Hit enter ot add the IP Server Interface.
3. Add an entry in the /etc/hosts file for the remote system(s)
Example: 9.19.130.184 myppp
4. Find the hardware address of the local adapter with netstat -i
Name Mtu Network Address Ipkts Ierrs Opkts Oerrs Coll
lo0 16896 3000580 0 3000580 0 0
lo0 16896 127 localhost 3000580 0 3000580 0 0
tr0 1492 10.0.5a.a8.84.9d 65426841 0 2019080 0 0
tr0 1492 9.19.128 tesch.aix.dfw.i 65426841 0 2019080 0 0
5. Turn on ipforwarding with: no ipforwarding=1
6. Add an arp entry for the remote host.
o Format: arp -s type hostname hardware address [temp] [pub]
o Example: arp -s 802.5 myppp 10:00:5a:a8:84:9d pub
+ The type (802.5) is the type of the adapter card that will
respond the the request. Types: ether, 802.3, fddi, 802.5.
+ hostname: name entered in /etc/hosts table.
+ hardware address from netstat -i (with colon separaters).
+ pub makes it public, temp would make it only temporary. You
may have to add this arp command to /etc/rc.net to hold over
boot.
o netstat -i will now show:
pp0 1500 15 0 91 0 0
pp0 1500 9.19.128 tesch.aix.dfw.i 15 0 91 0 0
7. Dial in from client system - see cookbook.
If this is an AIX client use:
/usr/sbin/pppattachd ttyX client connect "/usr/sbin/pppdial -v -f
script
8. ifconfig pp0 will tell you when the link is up.
pp0: flags=71
inet 9.19.129.12 --> 9.19.130.184 netmask 0xfffff000
9. Look at the the routing table with netstat -rn
Routing tables
Destination Gateway Flags Refs Use Interface
Netmasks:
255
(0) 0 ffff ff00
255.255.240
Route Tree for Protocol Family 2:
default 9.19.141.241 UG 4 216655 tr0
9.19.128 9.19.129.12 U 32 4602124 tr0
9.19.130.184 9.19.129.12 UH 2 101 pp0
127 127.0.0.1 U 1 502 lo0
10. Users anywhere on the local network will now be able to use the
interface.
Support Line: Using PPP and Proxy arp ITEM: BJ8586L
Dated: June 1996 Category: N/A
This HTML file was generated 99/06/24~13:30:21
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