[syslinux] syslinux6 EFI fail to boot via pxe

Michael Szerencsits szerencsits.michael at gmx.at
Tue Jun 25 06:14:00 PDT 2013


> Isn't the server complaining because port 7012 is unreachable? Not the
> other way around? It really doesn't matter to the server what the value
> of the source port is from the client.
> 
> Looking at your network packet dump from a previous email,
> 
> Source       Destination  Protocal   SPort    DPort    Description
> 10.0.0.100   10.0.0.1     tftp       1479     69       Read Request:File /syslinux/ldlinux.e32, Transfer type: octet, tsize\000=0\000,blksize\000=1408\000
> 10.0.0.1     10.0.0.100   tftp       7018     1479     Option Acknoledgment, tsize\000=117160\000, blksize\000=1408\000
> 10.0.0.100   10.0.0.1     udp        1480     7018     Source port:1480 Destination port: 7018
> 
> 
> The client is trying to connect to port 7018 on the server, but the
> server responds with...
> 
> 
> 10.0.0.1     10.0.0.100   icmp                         Destination unreachable (Port unreachable)
> 
> 
> because a connection cannot be made to port 7018 on 10.0.0.1. No?
> 
> -- 
> Matt Fleming, Intel Open Source Technology Center
> 

Hi Matt,

the server is listening on the port. I reviewed the RFC for TFTP and it say that the server would response with an error if the source TID is not correct:

      1. Host A sends  a  "RRQ" or "WRQ" to  host  B  with  source=  A's  TID,
         destination= 69.

      2. Host  B  sends  a "ACK" (with block number= 0) to host A with
         source= B's TID, destination= A's TID.

   At this point the connection has been established and the first data
   packet can be sent by Host A with a sequence number of 1.  In the
   next step, and in all succeeding steps, the hosts should make sure
   that the source TID matches the value that was agreed on in steps 1
   and 2.  If a source TID does not match, the packet should be
   discarded as erroneously sent from somewhere else.  An error packet
   should be sent to the source of the incorrect packet, while not
   disturbing the transfer.

I also review how you do this for BIOS mode, but there you use a other methode (re_connect with different source port)

Regards
Michael


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