Re: CNAME lookup failure started
Vahid Moghaddasi <[email protected]> Tue, 12 Oct 2010 11:41:23 -0400
| Newsgroups | gmane.network.djbdns,gmane.mail.qmail.general |
|---|---|
| Message-ID | <[email protected]> |
--00163630f3971ebac404926d4f55 Content-Type: text/plain; charset=ISO-8859-1 On Mon, Oct 11, 2010 at 6:04 PM, Mark Johnson <[email protected]> wrote: > On Thu, Oct 7, 2010 at 2:28 PM, Erwin Hoffmann <[email protected]> wrote: > >> However, I use a patched version of djbdns allowing 'big' UDP packets >> (common these days). I suggest to enhance the value of 'udpbuf' in >> dns_transmit.c to 1200 byte: >> >> int dns_transmit_get(struct dns_transmit *d,const iopause_fd *x,const >> struct taia *when) >> { >> char udpbuf[1200]; >> unsigned char ch; >> int r; >> int fd; >> >> Remember: The original maximum size for UDP packets was due to the IPv4 >> MTU constraints, roughly about 500 byte. Current networks -- able to >> transmit IPv6 packets -- need to support a minimum MTU of 1280 byte. >> >> Change that value and recompile. This changed value will now be the >> standard maximum size of all djbdns traffic. >> >> regards. >> --eh. >> >> -- >> Dr. Erwin Hoffmann | FEHCom | http://www.fehcom.de >> > > FYI, I merged a similar fix (patch from Matthew Dempsky) into zinq-djbdns a > while back: > > > http://zinq.svn.sourceforge.net/viewvc/zinq/dns/trunk/dns_transmit.c?r1=51&r2=66 > http://marc.info/?l=djbdns&m=122368590802063&w=2 > I have all the necessary patches for oversised UDP packets but what I am not clear is why everyone is thinking this is a DJBdns problem? I tried this on any machine and get the same result, regardless of the DNS server. dig -t any IX.NETCOM.COM will hang but when you do dig -t mx IX.NETCOM.COMeverything is ok a while and dig -t any IX.NETCOM.COM will no longer hangs for a few hours. --00163630f3971ebac404926d4f55 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable <div class=3D"gmail_quote">On Mon, Oct 11, 2010 at 6:04 PM, Mark Johnson <s= pan dir=3D"ltr"><<a href=3D"mailto:[email protected]">[email protected]= m</a>></span> wrote:<br> <blockquote style=3D"BORDER-LEFT: #ccc 1px solid; MARGIN: 0px 0px 0px 0.8ex= ; PADDING-LEFT: 1ex" class=3D"gmail_quote"> <div class=3D"im">On Thu, Oct 7, 2010 at 2:28 PM, Erwin Hoffmann <span dir= =3D"ltr"><<a href=3D"mailto:[email protected]" target=3D"_blank">feh@fehcom.= de</a>></span> wrote:<br> <div class=3D"gmail_quote"> <blockquote style=3D"BORDER-LEFT: rgb(204,204,204) 1px solid; MARGIN: 0pt 0= pt 0pt 0.8ex; PADDING-LEFT: 1ex" class=3D"gmail_quote">However, I use a pat= ched version of djbdns allowing 'big' UDP packets<br>(common these = days). I suggest to enhance the value of 'udpbuf' in<br> dns_transmit.c to 1200 byte:<br><br>int dns_transmit_get(struct dns_transmi= t *d,const iopause_fd *x,const<br>struct taia *when)<br>{<br>=A0char udpbuf= [1200];<br>=A0unsigned char ch;<br>=A0int r;<br>=A0int fd;<br><br>Remember:= The original maximum size for UDP packets was due to the IPv4<br> MTU constraints, roughly about 500 byte. Current networks -- able to<br>tra= nsmit IPv6 packets -- need to support a minimum MTU of 1280 byte.<br><br>Ch= ange that value and recompile. This changed value will now be the<br>standa= rd maximum size of all djbdns traffic.<br> <br>regards.<br>--eh.<br><font color=3D"#888888"><br>--<br>Dr. Erwin Hoffma= nn | FEHCom | <a href=3D"http://www.fehcom.de/" target=3D"_blank">http://ww= w.fehcom.de</a><br></font></blockquote></div><br></div>FYI, I merged a simi= lar fix (patch from Matthew Dempsky) into zinq-djbdns a while back:<br> <br><a href=3D"http://zinq.svn.sourceforge.net/viewvc/zinq/dns/trunk/dns_tr= ansmit.c?r1=3D51&r2=3D66" target=3D"_blank">http://zinq.svn.sourceforge= .net/viewvc/zinq/dns/trunk/dns_transmit.c?r1=3D51&r2=3D66</a><br><a hre= f=3D"http://marc.info/?l=3Ddjbdns&m=3D122368590802063&w=3D2" target= =3D"_blank">http://marc.info/?l=3Ddjbdns&m=3D122368590802063&w=3D2<= /a><br> </blockquote></div> <div><br>=A0</div> <div>I have all the necessary patches for oversised UDP packets but what I = am not clear is why everyone is thinking this is a DJBdns problem?</div> <div>I tried this on any machine and get the same result, regardless of the= DNS server.</div> <div>dig -t any <a href=3D"http://IX.NETCOM.COM">IX.NETCOM.COM</a> will han= g but when you do dig -t mx <a href=3D"http://IX.NETCOM.COM">IX.NETCOM.COM<= /a> everything is ok a while and dig -t any <a href=3D"http://IX.NETCOM.COM= ">IX.NETCOM.COM</a> will no longer hangs for a few hours.</div> <div>=A0</div> --00163630f3971ebac404926d4f55--