I tested with 1.5.14. I think this is not a regression. The error is the same.
But using insert instead of prefix, also with 1.5.6 the strange cookie is managed in different manner "strange cookie" has a prefix, probably taken by old haproxy connection with prefix, this old cookie is marked ---NI instead of ---IN and haproxy now configured with insert instead of prefix, insert a cookie so all works well. I think this is a bug or something you can manage in haproxy. If not only cookie insert can be used to have a robust cookie / session management with haproxy. And more... Can be used sticky table as insert mode ? without specify an application cookie ? This is the BLOCK1 Jul 20 14:39:49 haproxy_machine haproxy[2846]: 172.16.3.122:7144 [20/Jul/2015:14:39:49.411] front_end~ back_end/SERVER1 132/0/1/89/222 302 541 ASP.NET_SessionId=SERVER1_https~3k5uin550flaxa55dl1twd45 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 --NI 1/1/0/1/0 0/0 "GET /app1/ HTTP/1.1" Jul 20 14:39:49 haproxy_machine haproxy[2846]: 172.16.3.122:7144 [20/Jul/2015:14:39:49.633] front_end~ back_end/SERVER1 3/0/1/11/15 200 6444 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 1/1/0/1/0 0/0 "GET /app1/login.aspx HTTP/1.1" Jul 20 14:39:49 haproxy_machine haproxy[2846]: 172.16.3.122:7144 [20/Jul/2015:14:39:49.649] front_end~ back_end/SERVER1 7/0/1/6/14 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 1/1/0/1/0 0/0 "GET /app1/templatelibrary/menutop/templatenoheader.css HTTP/1.1" Jul 20 14:39:49 haproxy_machine haproxy[2846]: 172.16.3.122:7144 [20/Jul/2015:14:39:49.664] front_end~ back_end/SERVER1 1/0/1/9/11 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 3/3/1/2/0 0/0 "GET /app1/templatelibrary/menutop/img/logoheader/logo.gif HTTP/1.1" Jul 20 14:39:49 haproxy_machine haproxy[2846]: 172.16.3.122:7146 [20/Jul/2015:14:39:49.664] front_end~ back_end/SERVER1 2/0/1/11/14 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 3/3/0/1/0 0/0 "GET /app1/templatelibrary/menutop/common.css HTTP/1.1" Jul 20 14:39:49 haproxy_machine haproxy[2846]: 172.16.3.122:7144 [20/Jul/2015:14:39:49.675] front_end~ back_end/SERVER1 8/0/1/8/17 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 3/3/1/2/0 0/0 "GET /app1/templatelibrary/menutop/aps/jquery-ui-1.10.3.custom.min.css HTTP/1.1" Jul 20 14:39:49 haproxy_machine haproxy[2846]: 172.16.3.122:7146 [20/Jul/2015:14:39:49.679] front_end~ back_end/SERVER1 3/0/1/14/18 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 3/3/0/1/0 0/0 "GET /app1/templatelibrary/menutop/jquery.multiselect.css HTTP/1.1" Jul 20 14:39:56 haproxy_machine haproxy[2846]: 172.16.3.122:7146 [20/Jul/2015:14:39:49.697] front_end~ back_end/SERVER1 6495/0/3/132/6630 302 6481 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 3/3/0/1/0 0/0 "POST /app1/login.aspx HTTP/1.1" Jul 20 14:39:56 haproxy_machine haproxy[2846]: 172.16.3.122:7146 [20/Jul/2015:14:39:56.327] front_end~ back_end/SERVER1 3/0/1/138/143 200 21668 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 3/3/0/0/0 0/0 "GET /app1/ HTTP/1.1" Jul 20 14:39:56 haproxy_machine haproxy[2846]: 172.16.3.122:7159 [20/Jul/2015:14:39:56.486] front_end~ back_end/SERVER1 4/0/1/1/6 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/3/4/0 0/0 "GET /app1/templatelibrary/menutop/img/module5.gif HTTP/1.1" Jul 20 14:39:56 haproxy_machine haproxy[2846]: 172.16.3.122:7144 [20/Jul/2015:14:39:49.692] front_end~ back_end/SERVER1 6796/0/1/9/6806 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/3/4/0 0/0 "GET /app1/templatelibrary/menutop/img/homebackground/proclist.jpg HTTP/1.1" Jul 20 14:39:56 haproxy_machine haproxy[2846]: 172.16.3.122:7159 [20/Jul/2015:14:39:56.493] front_end~ back_end/SERVER1 1/0/1/2/4 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/2/3/0 0/0 "GET /app1/templatelibrary/menutop/img/module2.gif HTTP/1.1" Jul 20 14:39:56 haproxy_machine haproxy[2846]: 172.16.3.122:7147 [20/Jul/2015:14:39:49.667] front_end~ back_end/SERVER1 6821/0/2/10/6833 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/1/2/0 0/0 "GET /app1/templatelibrary/menutop/img/module0.gif HTTP/1.1" Jul 20 14:39:56 haproxy_machine haproxy[2846]: 172.16.3.122:7146 [20/Jul/2015:14:39:56.471] front_end~ back_end/SERVER1 13/0/1/51/65 304 183 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/0/1/0 0/0 "GET /app1/script/common.js HTTP/1.1" Jul 20 14:39:56 haproxy_machine haproxy[2846]: 172.16.3.122:7144 [20/Jul/2015:14:39:56.497] front_end~ back_end/SERVER1 51/0/1/1/53 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/2/3/0 0/0 "GET /app1/templatelibrary/menutop/img/module1.gif HTTP/1.1" Jul 20 14:39:56 haproxy_machine haproxy[2846]: 172.16.3.122:7159 [20/Jul/2015:14:39:56.497] front_end~ back_end/SERVER1 51/0/2/1/54 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/1/2/0 0/0 "GET /app1/templatelibrary/menutop/img/module4.gif HTTP/1.1" Jul 20 14:39:56 haproxy_machine haproxy[2846]: 172.16.3.122:7147 [20/Jul/2015:14:39:56.499] front_end~ back_end/SERVER1 49/0/2/1/52 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/0/1/0 0/0 "GET /app1/templatelibrary/menutop/img/module3.gif HTTP/1.1" Jul 20 14:39:57 haproxy_machine haproxy[2846]: 172.16.3.122:7147 [20/Jul/2015:14:39:56.551] front_end~ back_end/SERVER1 1021/0/2/1/1024 301 448 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/0/1/0 0/0 "GET /app1/anagrafenet HTTP/1.1" Jul 20 14:39:57 haproxy_machine haproxy[2846]: 172.16.3.122:7147 [20/Jul/2015:14:39:57.576] front_end~ back_end/SERVER1 2/0/1/177/181 200 28896 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/0/0/0 0/0 "GET /app1/anagrafenet/ HTTP/1.1" Jul 20 14:39:57 haproxy_machine haproxy[2846]: 172.16.3.122:7144 [20/Jul/2015:14:39:56.551] front_end~ back_end/SERVER1 1280/0/1/14/1295 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/5/6/0 0/0 "GET /app1/css/procedure.css HTTP/1.1" Jul 20 14:39:57 haproxy_machine haproxy[2846]: 172.16.3.122:7146 [20/Jul/2015:14:39:56.537] front_end~ back_end/SERVER1 1295/0/1/18/1314 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/4/5/0 0/0 "GET /app1/templatelibrary/menutop/sf-menu.css HTTP/1.1" Jul 20 14:39:57 haproxy_machine haproxy[2846]: 172.16.3.122:7161 [20/Jul/2015:14:39:56.488] front_end~ back_end/SERVER1 1343/0/2/28/1373 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/4/5/0 0/0 "GET /app1/menu/supersubs.js HTTP/1.1" Jul 20 14:39:57 haproxy_machine haproxy[2846]: 172.16.3.122:7160 [20/Jul/2015:14:39:56.488] front_end~ back_end/SERVER1 1344/0/2/28/1374 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/3/4/0 0/0 "GET /app1/menu/hoverintent.js HTTP/1.1" Jul 20 14:39:57 haproxy_machine haproxy[2846]: 172.16.3.122:7147 [20/Jul/2015:14:39:57.757] front_end~ back_end/SERVER1 71/0/1/38/110 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/2/3/0 0/0 "GET /app1/script/dwfunctions.js HTTP/1.1" Jul 20 14:39:57 haproxy_machine haproxy[2846]: 172.16.3.122:7144 [20/Jul/2015:14:39:57.846] front_end~ back_end/SERVER1 13/0/2/16/31 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/1/2/0 0/0 "GET /app1/menu/superfish.js HTTP/1.1" Jul 20 14:39:57 haproxy_machine haproxy[2846]: 172.16.3.122:7159 [20/Jul/2015:14:39:56.551] front_end~ back_end/SERVER1 1277/0/1/74/1352 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/0/1/0 0/0 "GET /app1/script/jquery.min.js HTTP/1.1" Jul 20 14:39:57 haproxy_machine haproxy[2846]: 172.16.3.122:7159 [20/Jul/2015:14:39:57.904] front_end~ back_end/SERVER1 39/0/1/11/51 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/0/1/0 0/0 "GET /app1/templatelibrary/menutop/superfish.css HTTP/1.1" Jul 20 14:39:57 haproxy_machine haproxy[2846]: 172.16.3.122:7159 [20/Jul/2015:14:39:57.955] front_end~ back_end/SERVER1 5/0/1/15/21 200 10688 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/0/0/0 0/0 "GET /app1/anagrafenet/home.aspx HTTP/1.1" Jul 20 14:39:58 haproxy_machine haproxy[2846]: 172.16.3.122:7159 [20/Jul/2015:14:39:57.976] front_end~ back_end/SERVER1 101/0/1/2/104 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/0/1/0 0/0 "GET /app1/templatelibrary/menutop/img/arrows-006699.png HTTP/1.1" Jul 20 14:39:58 haproxy_machine haproxy[2846]: 172.16.3.122:7147 [20/Jul/2015:14:39:57.868] front_end~ back_end/SERVER1 239/0/1/1/241 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/5/6/0 0/0 "GET /app1/templatelibrary/menutop/img/apps.gif HTTP/1.1" Jul 20 14:39:58 haproxy_machine haproxy[2846]: 172.16.3.122:7161 [20/Jul/2015:14:39:57.862] front_end~ back_end/SERVER1 245/0/2/1/248 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/4/5/0 0/0 "GET /app1/templatelibrary/menutop/img/apsnet.gif HTTP/1.1" Jul 20 14:39:58 haproxy_machine haproxy[2846]: 172.16.3.122:7146 [20/Jul/2015:14:39:57.851] front_end~ back_end/SERVER1 256/0/2/1/259 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/3/4/0 0/0 "GET /app1/templatelibrary/menutop/img/reco.gif HTTP/1.1" Jul 20 14:39:58 haproxy_machine haproxy[2846]: 172.16.3.122:7160 [20/Jul/2015:14:39:57.863] front_end~ back_end/SERVER1 245/0/3/1/249 304 183 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/2/3/0 0/0 "GET /app1/templatelibrary/menutop/img/help.gif HTTP/1.1" Jul 20 14:39:58 haproxy_machine haproxy[2846]: 172.16.3.122:7144 [20/Jul/2015:14:39:57.877] front_end~ back_end/SERVER1 228/0/1/10/239 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/1/2/0 0/0 "GET /app1/templatelibrary/menutop/templateresponsive.css HTTP/1.1" Jul 20 14:39:58 haproxy_machine haproxy[2846]: 172.16.3.122:7159 [20/Jul/2015:14:39:58.080] front_end~ back_end/SERVER1 24/0/1/20/45 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/1/2/0 0/0 "GET /app1/script/bootstrap-3.2.0/css/bootstrap.min.css HTTP/1.1" Jul 20 14:39:58 haproxy_machine haproxy[2846]: 172.16.3.122:7144 [20/Jul/2015:14:39:58.116] front_end~ back_end/SERVER1 2/0/1/10/13 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/0/1/0 0/0 "GET /app1/templatelibrary/menutop/commonresponsive.css HTTP/1.1" Jul 20 14:39:58 haproxy_machine haproxy[2846]: 172.16.3.122:7144 [20/Jul/2015:14:39:58.129] front_end~ back_end/SERVER1 6/0/1/5/12 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/0/1/0 0/0 "GET /app1/script/bootstrap-3.3.4/css/bootstrap.min.css HTTP/1.1" Jul 20 14:39:58 haproxy_machine haproxy[2846]: 172.16.3.122:7144 [20/Jul/2015:14:39:58.142] front_end~ back_end/SERVER1 12/0/1/7/20 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/1/2/0 0/0 "GET /app1/templatelibrary/menutop/loading.html HTTP/1.1" Jul 20 14:39:58 haproxy_machine haproxy[2846]: 172.16.3.122:7159 [20/Jul/2015:14:39:58.125] front_end~ back_end/SERVER1 33/0/2/11/46 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/1/2/0 0/0 "GET /app1/templatelibrary/menutop/img/homebackground/anagrafenet.gif HTTP/1.1" Jul 20 14:39:58 haproxy_machine haproxy[2846]: 172.16.3.122:7144 [20/Jul/2015:14:39:58.163] front_end~ back_end/SERVER1 4/0/1/11/16 304 183 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/0/1/0 0/0 "GET /app1/templatelibrary/menutop/img/loading.gif HTTP/1.1" Jul 20 14:39:58 haproxy_machine haproxy[2846]: 172.16.3.122:7144 [20/Jul/2015:14:39:58.179] front_end~ back_end/SERVER1 3/0/1/23/27 200 5378 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/0/1/0 0/0 "GET /app1/getnews.aspx HTTP/1.1" Jul 20 14:40:02 haproxy_machine haproxy[2846]: 172.16.3.122:7144 [20/Jul/2015:14:39:58.207] front_end~ back_end/SERVER1 4376/0/1/86/4465 200 48280 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/0/1/0 0/0 "GET /app1/anagrafenet/cartellinosintetico.aspx?fromMenu=1 HTTP/1.1" Jul 20 14:40:02 haproxy_machine haproxy[2846]: 172.16.3.122:7144 [20/Jul/2015:14:40:02.672] front_end~ back_end/SERVER1 9/0/1/9/19 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/5/6/0 0/0 "GET /app1/templatelibrary/menutop/submodal.css HTTP/1.1" Jul 20 14:40:02 haproxy_machine haproxy[2846]: 172.16.3.122:7159 [20/Jul/2015:14:39:58.171] front_end~ back_end/SERVER1 4510/0/2/18/4530 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/5/6/0 0/0 "GET /app1/templatelibrary/menutop/scripts/common.js HTTP/1.1" Jul 20 14:40:02 haproxy_machine haproxy[2846]: 172.16.3.122:7146 [20/Jul/2015:14:39:58.110] front_end~ back_end/SERVER1 4574/0/2/18/4594 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/5/6/0 0/0 "GET /app1/script/apsrollover.js HTTP/1.1" Jul 20 14:40:02 haproxy_machine haproxy[2846]: 172.16.3.122:7159 [20/Jul/2015:14:40:02.702] front_end~ back_end/SERVER1 2/0/1/9/12 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/5/6/0 0/0 "GET /app1/templatelibrary/menutop/img/exit.gif HTTP/1.1" Jul 20 14:40:02 haproxy_machine haproxy[2846]: 172.16.3.122:7146 [20/Jul/2015:14:40:02.704] front_end~ back_end/SERVER1 1/0/1/8/10 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/4/5/0 0/0 "GET /app1/templatelibrary/menutop/img/search.gif HTTP/1.1" Jul 20 14:40:02 haproxy_machine haproxy[2846]: 172.16.3.122:7161 [20/Jul/2015:14:39:58.110] front_end~ back_end/SERVER1 4574/0/2/29/4605 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/3/4/0 0/0 "GET /app1/script/webuiconfirmation.js HTTP/1.1" Jul 20 14:40:02 haproxy_machine haproxy[2846]: 172.16.3.122:7144 [20/Jul/2015:14:40:02.692] front_end~ back_end/SERVER1 1/0/1/23/25 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/2/3/0 0/0 "GET /app1/script/webuiconfirmationstartup.js HTTP/1.1" Jul 20 14:40:02 haproxy_machine haproxy[2846]: 172.16.3.122:7160 [20/Jul/2015:14:39:58.111] front_end~ back_end/SERVER1 4572/0/2/32/4606 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/1/2/0 0/0 "GET /app1/templatelibrary/menutop/scripts/submodal.js HTTP/1.1" Jul 20 14:40:02 haproxy_machine haproxy[2846]: 172.16.3.122:7159 [20/Jul/2015:14:40:02.715] front_end~ back_end/SERVER1 3/0/1/1/5 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/1/2/0 0/0 "GET /app1/templatelibrary/menutop/img/cerca.gif HTTP/1.1" Jul 20 14:40:02 haproxy_machine haproxy[2846]: 172.16.3.122:7147 [20/Jul/2015:14:39:58.108] front_end~ back_end/SERVER1 4576/0/2/49/4627 304 183 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/0/1/0 0/0 "GET /app1/script/calendar.js HTTP/1.1" Jul 20 14:40:02 haproxy_machine haproxy[2846]: 172.16.3.122:7147 [20/Jul/2015:14:40:02.736] front_end~ back_end/SERVER1 69/0/1/13/83 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/0/1/0 0/0 "GET /app1/templatelibrary/menutop/img/tab_right.gif HTTP/1.1" Jul 20 14:40:02 haproxy_machine haproxy[2846]: 172.16.3.122:7159 [20/Jul/2015:14:40:02.720] front_end~ back_end/SERVER1 109/0/2/1/112 304 183 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/1/2/0 0/0 "GET /app1/templatelibrary/menutop/img/maskbg.png HTTP/1.1" Jul 20 14:40:02 haproxy_machine haproxy[2846]: 172.16.3.122:7147 [20/Jul/2015:14:40:02.820] front_end~ back_end/SERVER1 10/0/2/11/23 304 184 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/0/1/0 0/0 "GET /app1/templatelibrary/menutop/img/closepopup.gif HTTP/1.1" Jul 20 14:40:03 haproxy_machine haproxy[2846]: 172.16.3.122:7147 [20/Jul/2015:14:40:02.843] front_end~ back_end/SERVER1 916/0/1/85/1004 200 60107 ASP.NET_SessionId=qbasnn45mfhxi155lyncbw45 - --VN 6/6/0/1/0 0/0 "GET /app1/anagrafenet/cartellinoindividuale.aspx?fromMenu=1 HTTP/1.1" This is the BLOCK2 Jul 20 14:40:14 haproxy_machine haproxy[2846]: 172.16.3.122:7191 [20/Jul/2015:14:40:13.144] front_end~ back_end/SERVER2 1356/0/2/2/1360 301 424 ASP.NET_SessionId=SERVER2_https~ka5bepio0kdrc145g2p32pak - --NI 6/6/0/1/0 0/0 "GET /app1 HTTP/1.1" Jul 20 14:40:14 haproxy_machine haproxy[2846]: 172.16.3.122:7191 [20/Jul/2015:14:40:14.505] front_end~ back_end/SERVER2 238/0/2/65/305 302 541 ASP.NET_SessionId=SERVER2_https~ka5bepio0kdrc145g2p32pak ASP.NET_SessionId=tahvauvuahzipfuq2fisio55 --VN 6/6/0/1/0 0/0 "GET /app1/ HTTP/1.1" Jul 20 14:40:14 haproxy_machine haproxy[2846]: 172.16.3.122:7191 [20/Jul/2015:14:40:14.810] front_end~ back_end/SERVER2 63/0/1/27/91 200 6449 ASP.NET_SessionId=tahvauvuahzipfuq2fisio55 - --VN 6/6/0/1/0 0/0 "GET /app1/login.aspx HTTP/1.1" Jul 20 14:40:15 haproxy_machine haproxy[2846]: 172.16.3.122:7191 [20/Jul/2015:14:40:14.901] front_end~ back_end/SERVER2 711/0/2/2/715 200 1078 ASP.NET_SessionId=tahvauvuahzipfuq2fisio55 - --VN 6/6/0/1/0 0/0 "GET /app1/templatelibrary/menutop/templatenoheader.css HTTP/1.1" Jul 20 14:40:15 haproxy_machine haproxy[2846]: 172.16.3.122:7195 [20/Jul/2015:14:40:13.145] front_end~ back_end/SERVER2 2518/0/3/10/2531 304 184 ASP.NET_SessionId=tahvauvuahzipfuq2fisio55 - --VN 6/6/0/1/0 0/0 "GET /app1/templatelibrary/menutop/img/logoheader/logo.gif HTTP/1.1" Jul 20 14:40:16 haproxy_machine haproxy[2846]: 172.16.3.122:7191 [20/Jul/2015:14:40:15.615] front_end~ back_end/SERVER2 508/0/2/2/512 304 111 ASP.NET_SessionId=tahvauvuahzipfuq2fisio55 - --VN 6/6/0/1/0 0/0 "GET /app1/templatelibrary/menutop/common.css HTTP/1.1" Jul 20 14:40:16 haproxy_machine haproxy[2846]: 172.16.3.122:7195 [20/Jul/2015:14:40:15.677] front_end~ back_end/SERVER2 472/0/2/1/475 304 112 ASP.NET_SessionId=tahvauvuahzipfuq2fisio55 - --VN 6/6/1/2/0 0/0 "GET /app1/templatelibrary/menutop/aps/jquery-ui-1.10.3.custom.min.css HTTP/1.1" Jul 20 14:40:16 haproxy_machine haproxy[2846]: 172.16.3.122:7191 [20/Jul/2015:14:40:16.126] front_end~ back_end/SERVER2 21/0/3/2/26 304 183 ASP.NET_SessionId=tahvauvuahzipfuq2fisio55 - --VN 6/6/0/1/0 0/0 "GET /app1/templatelibrary/menutop/jquery.multiselect.css HTTP/1.1" Jul 20 14:40:39 haproxy_machine haproxy[2846]: 172.16.3.122:7237 [20/Jul/2015:14:40:38.919] front_end~ back_end/SERVER2 29/0/56/74/159 302 6486 ASP.NET_SessionId=tahvauvuahzipfuq2fisio55 - --VN 1/1/0/1/0 0/0 "POST /app1/login.aspx HTTP/1.1" Jul 20 14:40:39 haproxy_machine haproxy[2846]: 172.16.3.122:7237 [20/Jul/2015:14:40:39.078] front_end~ back_end/SERVER2 3/0/1/158/163 200 21673 ASP.NET_SessionId=tahvauvuahzipfuq2fisio55 - --VN 1/1/0/0/0 0/0 "GET /app1/ HTTP/1.1" Jul 20 14:40:39 haproxy_machine haproxy[2846]: 172.16.3.122:7237 [20/Jul/2015:14:40:39.242] front_end~ back_end/SERVER2 63/0/1/1/65 200 1229 ASP.NET_SessionId=tahvauvuahzipfuq2fisio55 - --VN 5/5/0/1/0 0/0 "GET /app1/script/common.js HTTP/1.1" Jul 20 14:40:39 haproxy_machine haproxy[2846]: 172.16.3.122:7243 [20/Jul/2015:14:40:39.308] front_end~ back_end/SERVER2 3/0/2/3/8 304 184 ASP.NET_SessionId=tahvauvuahzipfuq2fisio55 - --VN 6/6/4/5/0 0/0 "GET /app1/templatelibrary/menutop/img/module1.gif HTTP/1.1" Jul 20 14:40:39 haproxy_machine haproxy[2846]: 172.16.3.122:7239 [20/Jul/2015:14:40:39.306] front_end~ back_end/SERVER2 4/0/3/5/12 304 184 ASP.NET_SessionId=tahvauvuahzipfuq2fisio55 - --VN 6/6/3/4/0 0/0 "GET /app1/templatelibrary/menutop/img/module5.gif HTTP/1.1" Jul 20 14:40:39 haproxy_machine haproxy[2846]: 172.16.3.122:7242 [20/Jul/2015:14:40:39.307] front_end~ back_end/SERVER2 4/0/6/2/12 304 184 ASP.NET_SessionId=tahvauvuahzipfuq2fisio55 - --VN 6/6/2/3/0 0/0 "GET /app1/templatelibrary/menutop/img/module2.gif HTTP/1.1" Jul 20 14:40:39 haproxy_machine haproxy[2846]: 172.16.3.122:7241 [20/Jul/2015:14:40:39.307] front_end~ back_end/SERVER2 3/0/5/12/20 304 184 ASP.NET_SessionId=tahvauvuahzipfuq2fisio55 - --VN 6/6/1/2/0 0/0 "GET /app1/templatelibrary/menutop/img/module0.gif HTTP/1.1" Jul 20 14:40:39 haproxy_machine haproxy[2846]: 172.16.3.122:7240 [20/Jul/2015:14:40:39.306] front_end~ back_end/SERVER2 4/0/4/23/31 304 184 ASP.NET_SessionId=tahvauvuahzipfuq2fisio55 - --VN 6/6/2/3/0 0/0 "GET /app1/templatelibrary/menutop/img/homebackground/proclist.jpg HTTP/1.1" Jul 20 14:40:39 haproxy_machine haproxy[2846]: 172.16.3.122:7237 [20/Jul/2015:14:40:39.308] front_end~ back_end/SERVER2 26/0/3/2/31 304 184 ASP.NET_SessionId=tahvauvuahzipfuq2fisio55 - --VN 6/6/1/2/0 0/0 "GET /app1/templatelibrary/menutop/img/module4.gif HTTP/1.1" Jul 20 14:40:39 haproxy_machine haproxy[2846]: 172.16.3.122:7241 [20/Jul/2015:14:40:39.327] front_end~ back_end/SERVER2 8/0/2/2/12 304 184 ASP.NET_SessionId=tahvauvuahzipfuq2fisio55 - --VN 6/6/0/1/0 0/0 "GET /app1/templatelibrary/menutop/img/module3.gif HTTP/1.1" Roberto -----Original Message----- From: Willy Tarreau [mailto:[email protected]] Sent: lunedì 20 luglio 2015 12.15 To: mlist Cc: 'Baptiste'; [email protected] Subject: Re: cookie prefix strange behavior On Mon, Jul 20, 2015 at 09:51:28AM +0000, mlist wrote: > Hi Willy > > >> Hi Baptiste, as you can see using prefix or sticky table we found this > >> invalid cookie problem. > >> > >> - Why without haproxy in the middle we do not have this problem ? why a > >> browser send an INVALID cookie ? > > >Because it learned it another way, maybe before you installed haproxy, > >maybe on a direct connection or anything. > > I'm sure enough this is not the case. After we get this behavior, we cleaned > all cookies. After some testing passing only by haproxy for these domain, we > get the problem again, with Chrome and with IE. OK, interesting. > >> - How we can match absence of prefix ? can be done directly by haproxy ? > > > I think haproxy should fix it, yes, otherwise it can continue this way > > forever. That said, it *will* break existing sessions, but if haproxy > > applies load balancing, such session will be broken as well. > > > What version is this, 1.6-dev or 1.5 ? > > What do you mean with: "it *will* break existing sessions" ? if we load > balance web application with haproxy, session coming in must have a cookie > inserted/prefixed by haproxy, I'm wrong ? if so any request with an Invalid > cookie is INVALID :D so no session will be broken... What I mean is that if the cookie is invalid, haproxy cannot use the cookie to decide what server to send the request to, so it will pick one server in the farm which is not necessarily the right one (in fact it has a (N-1)/N chance of picking a wrong one in a farm of N servers). That's why I think that haproxy should fix this when this happens. Most likely the problem is that once a wrong cookie flows from the client to the server, the server will not emit this cookie anymore so no prefixing will occur. For this reason I think that we should remove the invalid cookies from the requests when running in prefix mode. In order to know exactly how the situation happened, you'll need to look through all the logs affecting the client which exhibited the problem. The cookie flags will indicate when the cookie was inserted/prefixed, present or valid/invalid etc... And maybe we'll find what produces this situation. It is also possible that the cookie is built by the application using javascript. > We compiled from source "HA-Proxy version 1.6-dev2-25f4e3e 2015/07/10" OK thanks. Do you know if 1.5 also produces the same problem ? It could be a regression, though I don't remember that we ever touched that area recently. Willy -- Il messaggio e' stato analizzato alla ricerca di virus o contenuti pericolosi da MailScanner, ed e' risultato non infetto.
