{"id":5579,"date":"2011-08-20T12:44:15","date_gmt":"2011-08-20T12:44:15","guid":{"rendered":"http:\/\/www.beautifulwork.org\/?p=5579"},"modified":"2011-08-20T12:44:15","modified_gmt":"2011-08-20T12:44:15","slug":"parameters-tcp_retries2","status":"publish","type":"post","link":"https:\/\/www.trueangle.org\/index.php\/2011\/08\/20\/parameters-tcp_retries2\/","title":{"rendered":"parameters tcp_retries2"},"content":{"rendered":"
A UNIX Parameter <\/u><\/h5>\n
\n$cat \/proc\/sys\/net\/ipv4\/tcp_retries2\n15\n$\n\n<\/pre>\n
<\/p>\n
 Parameter Definition <\/u><\/h5>\n
\nHow  many  times  to   retry  before  killing  alive  TCP\nconnection. RFC1122 says that  the limit should be longer\nthan 100 sec.  It is too small number.  The default value\nof 15 corresponds to ~ 13 - 30 minutes, depending on RTO.\n\n<\/pre>\n
<\/p>\n
 Parameter Code Internals <\/u><\/h5>\n

\n snippet 1 <\/b>
\n{
\n                .procname       = \"tcp_retries2\",
\n                .data           = &sysctl_tcp_retries2,
\n                .maxlen         = sizeof(int),
\n                .mode           = 0644,
\n                .proc_handler   = proc_dointvec
\n        },<\/p>\n
 snippet 2 <\/b>
\n  if (retransmits_timed_out(sk, sysctl_tcp_retries1, 0, 0)) {
\n                        \/* Black hole detection *\/
\n                        tcp_mtu_probing(icsk, sk);<\/p>\n
                        dst_negative_advice(sk);
\n                }<\/p>\n
                retry_until = sysctl_tcp_retries2;
\n                if (sock_flag(sk, SOCK_DEAD)) {
\n                        const int alive = (icsk->icsk_rto < TCP_RTO_MAX);<\/p>\n
                        retry_until = tcp_orphan_retries(sk, alive);
\n                        do_reset = alive ||
\n                                !retransmits_timed_out(sk, retry_until, 0, 0);<\/p>\n
                        if (tcp_out_of_resources(sk, do_reset))
\n                                return 1;
\n                }<\/p>\n
<\/code>
\n<\/p>\n
 Related From Research Paper <\/u><\/h5>\n
\nA tool  for TCP  stack testing and  TCP\/IP fingerprinting\n(a.k.a.   OS  detection)   is  introduced.   While  tools\npresently exist  to do either  OS detection[1, 2]  or TCP\nstack testing[3, 4], the  methods they employ are limited\nby  the  techniques  and  analysis  performed,  sometimes\nresulting in incorrect re- sults or no results at all. We\nintroduce   synscan,  a  tool   whose  objective   is  to\nfingerprint     every      aspect     of     a     TCP\/IP\nimplementation.    synscan   is    not    meant   as    a\nproof-of-concept tool; rather, it  is a robust and useful\ntool which can  be used in addition to  others for TCP\/IP\nstack  testing and OS  de- tection.  synscan incorporates\nmost  of the  techiques used  by the  existing  tools and\nintroduces  a number  of new  ones.  synscan's  s primary\nadvantage is that each test begins with a TCP SYN segment\n(hence the name)  to an open port, giving  it the ability\nto   test  and  fingerprint   even  the   most  fortified\nhosts. Conclusive data from  large network scans and com-\nparisons  to   results  from  existing   tools  are  also\nreported.\n\nsource:\nSYNSCAN: Towards Complete TCP\/IP Fingerprinting\n                       Greg Taleck\n                    \n                    NFR Security, Inc.\n               5 Choke Cherry Rd, Suite 200\n                   Rockville, MD 20850\n\n\n\n\n<\/pre>\n","protected":false},"excerpt":{"rendered":"
A UNIX Parameter $cat \/proc\/sys\/net\/ipv4\/tcp_retries2 15 $ Parameter Definition How many times to retry before killing alive TCP connection. RFC1122 says that the limit should be longer than 100 sec. It is too small number. The default value of 15 corresponds to ~ 13 – 30 minutes, depending on RTO. Parameter Code Internals snippet 1 … <\/p>\n
Continue reading “parameters tcp_retries2”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[1],"tags":[1380,1385,1548],"_links":{"self":[{"href":"https:\/\/www.trueangle.org\/index.php\/wp-json\/wp\/v2\/posts\/5579"}],"collection":[{"href":"https:\/\/www.trueangle.org\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.trueangle.org\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.trueangle.org\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.trueangle.org\/index.php\/wp-json\/wp\/v2\/comments?post=5579"}],"version-history":[{"count":0,"href":"https:\/\/www.trueangle.org\/index.php\/wp-json\/wp\/v2\/posts\/5579\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.trueangle.org\/index.php\/wp-json\/wp\/v2\/media?parent=5579"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.trueangle.org\/index.php\/wp-json\/wp\/v2\/categories?post=5579"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.trueangle.org\/index.php\/wp-json\/wp\/v2\/tags?post=5579"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}