× The internal search function is temporarily non-functional. The current search engine is no longer viable and we are researching alternatives.
As a stop gap measure, we are using Google's custom search engine service.
If you know of an easy to use, open source, search engine ... please contact support@midrange.com.


  1.  Home
  2. MIDRANGE-L
  3. September 2005

Re: UDP Packet Source Address

Hi Larry -


Scenario:
    V5R2 iSeries with Physical IP address 172.30.0.29 and 172.30.0.37
and Virtual IP address 172.30.0.45 one one Ethernet line.
    NAS box wanting to use iSeries based RADIUS program to authenticate
users at IP 172.31.0.104.

So I get an inbound UDP packet delivered to port 1645 on address
172.30.0.45 from address 172.31.0.104.  The packet is processed by a
Java program and a respose packet is sent back to 172.31.0.104.
Unfortunately the source address of the response packet is 172.30.0.29
so the NAS box ignores it.  I can point the NAS at 172.30.0.37 but same
result, response packets come from 172.30.0.29.

What must be done to make the source address of the UDP response packet
be the same as the inbound packet?  Java does not allow us to set the
source IP for the packet as that probably breaks some RFC I would think.
This isn't exactly what you are asking for, but if you want all packets going to 172.31.0.104 coming from 172.30.0.45, I think you can do it with a routing entry for 172.31.0.104 with a preferred interface of the interface for 172.30.0.45.
This will NOT make the outgoing packets have the source address matching the destination address of the incoming packets. I think it WILL make the source address of the outgoing packets be 172.30.0.45 instead of 172.30.0.29 (as long as the 172.30.0.45 interface is active). 

Ken
http://www.ke9nr.net/
Opinions expressed are my own and do not necessarily represent the views
of my employer or anyone in their right mind.

As an Amazon Associate we earn from qualifying purchases.

This thread ...
Follow On AppleNews
Return to Archive home page | Return to MIDRANGE.COM home page

This mailing list archive is Copyright 1997-2024 by midrange.com and David Gibbs as a compilation work. Use of the archive is restricted to research of a business or technical nature. Any other uses are prohibited. Full details are available on our policy page. If you have questions about this, please contact [javascript protected email address].

Operating expenses for this site are earned using the Amazon Associate program and Google Adsense.