TFTP Virtual Service using LVS

[Joseph Mack NA3T]

On Thu, 11 Jan 2007, K Natarajan-A16638 wrote:

> LVS users,
>
> I am trying to create a TFTP virtual service using the binaries provided
> at www.ultramonkey.org. I want to support High Capacity, High
> Availability and Load Balancing on my TFTP virtual service where the
> Real servers directly respond to the client requests without having to
> go through Linux Director again.

With LVS, packets from the client go to the director before 
being forwarded to the realservers.

> I tried to create the service using the
> configuration provided at the link below.
>
> http://www.ultramonkey.org/3/topologies/hc-ha-lb-eg.html
>
> I was able to get the load balancing and high availability working

how do you know this?

> but I
> could not get the TFTP service to work.

this statement is incompatible with the first half of your 
sentence.

> Using ethereal I observed the
> following.
>
> The real server was responding to the client TFTP get request and
> sending a the first block of the file in a UDP packet with the virtual
> IP as the source IP address and arbitrary source port (say 33212). The
> TFTP client responds with an UDP acknowledgement message with the
> virtual IP address as the target IP address and the target port equal to
> 33212. This request goes to the Linux director which ignores the packet
> as it does not have any service running on 33212.

the request goes to the director, which being a router, 
forwards it to the realservers.

> Does LVS work for UDP based services?.

yes, but not many people are using it for UDP.

> How does the Linux Director
> distinguish between clients for UDP based services?.

by the client IP.

Joe
-- 
Joseph Mack NA3T EME(B,D), FM05lw North Carolina
jmack (at) wm7d (dot) net - azimuthal equidistant map
generator at http://www.wm7d.net/azproj.shtml
Homepage http://www.austintek.com/ It's GNU/Linux!