<html><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:14px"><div id="yui_3_16_0_1_1413493499834_20958"><br></div><div dir="ltr" id="yui_3_16_0_1_1413493499834_20956">This is for one of our masters which has about 20K zones and handles zone transfer traffic from few hundred of our slaves.</div> <div class="qtdSeparateBR"><br><br></div><div class="yahoo_quoted" style="display: block;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 14px;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div dir="ltr"> <font size="2" face="Arial"> On Thursday, October 16, 2014 2:27 PM, Barry Margolin <barmar@alum.mit.edu> wrote:<br> </font> </div> <br><br> <div class="y_msg_container">In article <<a ymailto="mailto:mailman.1083.1413494517.26362.bind-users@lists.isc.org" href="mailto:mailman.1083.1413494517.26362.bind-users@lists.isc.org">mailman.1083.1413494517.26362.bind-users@lists.isc.org</a>>,<br> Shawn Zhou <<a ymailto="mailto:shawnzhou00@yahoo.com" href="mailto:shawnzhou00@yahoo.com">shawnzhou00@yahoo.com</a>> wrote:<br><br>> Hello,<br>> While I was investigating potential SYN flooding warning messages on my Linux <br>> box for our DNS traffic,I was very surprised to see the backlog was set to <br>> very small numbers for BIND tcp sockets.<br>> strace showed backlog was '10' for listening socket for port 53 and '128' for <br>> listening socket for port 953 (rdnc traffic).<br>> I've restarted BIND after I updated somaxconn but BIND didn't pick up the <br>> value.<br>> Why doesn't BIND set the backlog to a huge number and let OSes reduce it to <br>> whatever somaxconn is? Or just set backlog to whatever is is set for <br>> somaxconn?<br><br>Since TCP queries should be infrequent, why does it need a high backlog?<br><br>It seems like it's already increasing it, IIRC the default is 5.<br><br>-- <br>Barry Margolin<br>Arlington, MA<br>_______________________________________________<br>Please visit <a href="https://lists.isc.org/mailman/listinfo/bind-users" target="_blank">https://lists.isc.org/mailman/listinfo/bind-users </a>to unsubscribe from this list<br><br>bind-users mailing list<br><a ymailto="mailto:bind-users@lists.isc.org" href="mailto:bind-users@lists.isc.org">bind-users@lists.isc.org</a><br><a href="https://lists.isc.org/mailman/listinfo/bind-users" target="_blank">https://lists.isc.org/mailman/listinfo/bind-users</a><br><br><br></div> </div> </div> </div> </div></body></html>