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<TITLE>Cannot change the "S" bit in DHCPv6 option 39</TITLE>
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<P><FONT SIZE=2 FACE="Arial">Hi,</FONT>
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<P><FONT SIZE=2 FACE="Arial">I am using dhclient (version 4.1.1) running in v6 mode. I am trying to use "fqdn.no-client-update" in the dhclient config file to inform the DHCP v6 server not to do the PTR RR update on the DNS server on behalf of the client. I found that placing "send fqdn.no-client-upate on (or off)" in the config file would actually change the "O" bit in option 39's flag field in the client's DHCPV6 confirm/solicit messages, this does not seem right. I would expect it to change the "S" bit instead. </FONT></P>
<P><FONT SIZE=2 FACE="Arial">Here is an excerpt from RFC 4704 section 4.1 - </FONT>
<BR><FONT SIZE=2 FACE="Courier New"> The format of the Flags field is:<BR>
<BR>
0 1 2 3 4 5 6 7<BR>
+-+-+-+-+-+-+-+-+<BR>
| MBZ |N|O|S|<BR>
+-+-+-+-+-+-+-+-+<BR>
<BR>
<BR>
The "S" bit indicates whether the server SHOULD or SHOULD NOT perform<BR>
the AAAA RR (FQDN-to-address) DNS updates. A client sets the bit to<BR>
0 to indicate that the server SHOULD NOT perform the updates and 1 to<BR>
indicate that the server SHOULD perform the updates. The state of<BR>
the bit in the reply from the server indicates the action to be taken<BR>
by the server; if it is 1, the server has taken responsibility for<BR>
AAAA RR updates for the FQDN.<BR>
<BR>
The "O" bit indicates whether the server has overridden the client's<BR>
preference for the "S" bit. A client MUST set this bit to 0. A<BR>
server MUST set this bit to 1 if the "S" bit in its reply to the<BR>
client does not match the "S" bit received from the client.<BR>
<BR>
The "N" bit indicates whether the server SHOULD NOT perform any DNS<BR>
updates. A client sets this bit to 0 to request that the server<BR>
SHOULD perform updates (the PTR RR and possibly the AAAA RR based on<BR>
the "S" bit) or to 1 to request that the server SHOULD NOT perform<BR>
any DNS updates. A server sets the "N" bit to indicate whether the<BR>
server SHALL (0) or SHALL NOT (1) perform DNS updates. If the "N"<BR>
bit is 1, the "S" bit MUST be 0.</FONT>
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<P><FONT SIZE=2 FACE="Courier New">This is my dhclient's config file - </FONT>
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<P><FONT SIZE=2 FACE="Courier New">send fqdn.encoded on; </FONT>
<BR><FONT SIZE=2 FACE="Courier New">request dhcp6.name-servers, dhcp6.domain-search, dhcp6.sntp-servers;</FONT>
<BR><FONT SIZE=2 FACE="Courier New">timeout 40; </FONT>
<BR><FONT SIZE=2 FACE="Courier New">select-timeout 4; </FONT>
<BR><FONT SIZE=2 FACE="Courier New">also request fqdn, dhcp6.fqdn;</FONT>
<BR><FONT SIZE=2 FACE="Courier New">send fqdn6.server-update on; </FONT>
<BR><FONT SIZE=2 FACE="Courier New">send fqdn6.no-client-update off; </FONT>
<BR><FONT SIZE=2 FACE="Courier New">send fqdn.server-update off;</FONT>
<BR><FONT SIZE=2 FACE="Courier New">send fqdn.no-client-update on; </FONT>
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<P><FONT SIZE=2 FACE="Courier New">Anyone has an idea if this might be a bug in the dhclient code?</FONT>
</P>
<P><FONT SIZE=2 FACE="Courier New">Thanks,<BR>
Weiwen</FONT><BR>
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