[Dnsmasq-discuss] 2.55 X 2.57: problem with option smtp-server

[Simon Kelley]

Carlos Carvalho wrote:
> In 2.55 we could say in dhcp-optsfile:
> 
> tag:aconcagua,tag:vl160,69,hoggar
> 
> However 2.57.1 complains: "bad IP address at line 21 of
> /etc/dnsmasq/dhcp-options"
> 
> Is this a bug in 57.1 or was it a bug in 55? rfc2132 says the length
> must be a multiple of 4 but doesn't say it must be the ipv4 address...
> The changelog doesn't mention anything.
> 


I think it's pretty clear that it should be an address, not a domain
name in the option: note the captions above the data fields.

------------------------------------------------------------
8.14. Simple Mail Transport Protocol (SMTP) Server Option

   The SMTP server option specifies a list of SMTP servers available to
   the client.  Servers SHOULD be listed in order of preference.

   The code for the SMTP server option is 69.  The minimum length for
   this option is 4 octets, and the length MUST always be a multiple of
   4.

    Code   Len         Address 1               Address 2
   +-----+-----+-----+-----+-----+-----+-----+-----+--
   | 69  |  n  |  a1 |  a2 |  a3 |  a4 |  a1 |  a2 |  ...
   +-----+-----+-----+-----+-----+-----+-----+-----+--
----------------------------------------------------------------


Improved sanity checking in the option-parsing code is picking this up
in 2.57. So, bug in the config, not a bug 2.57, arguably a bug in 2.55.

Note that this will not have worked correctly in 2.55, it probably sent
an all-zeros or all-ones address.


Cheers,

Simon.



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