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View the number of connections for all 80 ports Copy Code code as follows: Netstat-nat|grep-i "80″|wc-l to sort the connected IP by number of connections Copy Code code as follows: Netstat-ntu | awk ' {print $} ' | Cut-d:-f1 | Sort | uniq-c | Sort-n View TCP connection Status Copy Code code as follows: Netstat-nat |awk ' {print $} ' |sort|uniq-c|sort-rn Netstat-n | awk '/^tcp/{++s[$NF]}; End {for (a in S) print A, s[a]} ' Netstat

) | aptu | ar (ch | go) | as (te | us) | attw | au (di |-m | r | s) | avan | be (ck | ll | nq) | bi (lb | rd) | bl (ac | az) | br (e | v) w | bumb | bw-(n | u) | c55/| capi | ccwa | cdm-| cell | chtm | cldc | cmd-| co (mp | nd) | craw | da (it | ll | ng) | dbte | dc-s | devi | dica | dmob | do (c | p) o | ds (12 |-d) | el (49 | ai) | em (l2 | ul) | er (ic | k0) | esl8 | ez ([4-7] 0 | OS | wa | ze) | fetc | fly (-| _) | g1 u | g560 | gene | gf-5 | g-mo | go (. w | od) | gr (ad | un) | haie | hcit

Common command line 1 for troubleshooting in LINUX. view TCP connection status netstat-nat | awk '{print $6}' | sort | uniq-c | sort-rn www.2cto.com netstat-n | awk '/^ tcp/{++ S [$ NF]}; END {for (a in S) print a, S [a]} 'netstat-n | awk'/^ tcp/{++ state [$ NF]}; END {for (key in state) print key, "\ t ", state [key]} 'netstat-n | awk'/^ tcp/{++ arr [$ NF]}; END {for (k in arr) print k, "\ t ", arr [k]} 'netstat-n | awk'/^ tcp/{print $ NF} '| sort | uniq-c | sort-rn netstat-ant | awk' {print $

'/^ tcp/{++ arr [$ NF]}; END {for (k in arr) print k, "\ t ", arr [k]} 'netstat-n | awk'/^ tcp/{print $ NF} '| sort | uniq-c | sort-rn netstat-ant | awk' {print $ NF} '| Grep-V' [a-z]' | sort | uniq-c 2. for more than 20 requests, see netstat-anlp | grep 80 | grep tcp | awk '{print $5}' | awk-F: '{print $1}' | sort | uniq-c | sort-nr | head-n20 netstat-ant | awk '/: 80/{split ($5, ip, ":"); ++ A [ip [1]} END {for (I in A) print A [I], i} '| sort-rn |

delimiter are NUL, not newline-W,--check-chars=n Compare No Morethan N charactersinchLines--Help display this help and exit--version output version information and Exita field is a run of blanks (usually spaces and/or TABs), Thennon-blankcharacters. Fields is skipped before chars.Note: 'uniq' does not detect repeated lines unless they is adjacent. Want to sort The input first, or use 'sort-u' without 'Uni Q'. Also, comparisons honor the rules specified by 'lc_collate'.Cat tmp.txtaaaabbbbbb

] ' | Sort | Uniq-c Netstat-ant|awk '/ip:80/{split ($5,ip, ":"); ++s[ip[1]]}end{for (A in S) print S[a],a} ' |sort-n netstat-a Nt|awk '/:80/{split ($5,ip, ":"); ++s[ip[1]]}end{for (A in S) print s[a],a} ' |sort-rn|head-n ' awk ' begin{printf ("htt P_code\tcount_num\n ")}{count[$10]++}end{for (A in COUNT) printf a" \t\t "count[a]" \ n "} ' Top 20 IP Lookup requests (often used to find sources of attack): Netstat-anlp|grep 80|grep Tcp|awk ' {print $} ' |awk-f: ' {print $} ' |sor

a "\ t" COUNT [a] "\ n"} 'www.2cto.com 2. for more than 20 requests, see netstat-anlp | grep 80 | grep tcp | awk '{print $5}' | awk-F: '{print $1}' | sort | uniq-c | sort-nr | head-n20 netstat-ant | awk '/: 80/{split ($5, ip, ":"); ++ A [ip [1]} END {for (I in A) print A [I], i} '| sort-rn | head-n20 3. use tcpdump to sniff access to port 80 to see who has the highest tcpdump-I eth0-tnn dst port 80-c 1000

(ic|k0) |esl8|ez ([4-7]0|os|wa|ze) |fetc|fly (-|_) |g1 u|g560|gene|gf-5|g-mo|go (. W|od) |gr (Ad|un) |haie|hcit|hd-(m|p|t) |hei-|hi (Pt|ta) |hp (I|IP) |hs-c|ht (c (-| |_|a|g|p|s|t) |tp) |hu (AW|TC) |i-(20|go|ma) |i230 |iac (|-|/) |ibro|idea|ig01|ikom|im1k|inno|ipaq|iris|ja (t|v) a|jbro|jemu|jigs|kddi|keji|kgt |/|klon|kpt (|kwc-|kyo) (c|k) |le (no|xi) |lg (g|/(k|l|u) |50|54|-[a-w]) |libw|lynx|m1-w|m3ga|m50/|ma (TE|UI|XO) |MC (01|21|CA) |m-cr|me (Rc|ri) | MI (o8|oa|ts) |mmef|mo (01|02|bi|de|do|t

Linux Web Server Web site failure analysis, the specific contents are as follows System Connection Status article: 1. View TCP connection Status Netstat-nat |awk ' {print $} ' |sort|uniq-c|sort-rn netstat-n | awk '/^tcp/{++s[$NF]}; End {for (a in S) print A, s[a]} ' or netstat-n | awk '/^tcp/{++state[$NF]}; End {for (key) print key, "\ T", State[key]} ' netstat-n | awk '/^tcp/{++arr[$NF]}; End {to (k in arr) print K, "T", arr[k]} ' netstat-n |awk '/^tcp/{print $NF} ' |sort|uniq-c|sor

; @ ver1Port_string VERSION BANNER------------------- ---------- ----------------------------------------------------------------------------X86_64/linux 2.4.xx 11.2.0.4.0 Oracle Database 11g Enterprise Edition Release 11.2.0.4.0-64bit Production[Email protected]> show parameter session_cached_cursorsNAME TYPE VALUE---------------------- ------- -----Session_cached_cursors Integer 50[Email protected]> show parameter open_cursorsNAME TYPE VALUE------------ ------- -----Open_cursors Integer 300[Em

1. View TCP connection StatusNetstat-Nat|Awk' {print $6} '|Sort|Uniq-C|Sort-Rnnetstat-N|Awk'/^tcp/{++s[$NF]}; END {for (a in S) print A, s[a]} ' OrNetstat-N|Awk'/^tcp/{++state[$NF]}; END {for (key in) print key, "\ T", State[key]} 'Netstat-N|Awk'/^tcp/{++arr[$NF]}; END {for (k in arr) print K, "\ T", arr[k]} 'netstat -n | '/^tcp/{print $NF} ' | Sort| Uniq -c|-rnnetstat -ant | ' {print $NF} ' | grep Span class= "pun" >-v [a-z] ' || Uniq -c (The effect of each of these lines is basically th

View the number of connections for all 80 ports Netstat-nat|grep-i "|wc-l" To sort the connected IP by number of connections Netstat-ntu | awk ' {print $} ' | Cut-d:-f1 | Sort | uniq-c | Sort-n View TCP connection Status Netstat-nat |awk ' {print $} ' |sort|uniq-c|sort-rnNetstat-n | awk '/^tcp/{++s[$NF]}; End {for (a in S) print A, s[a]} 'Netstat-n | awk '/^tcp/{++state[$NF]}; End {for (key) print key, "\ T", State[key]} 'Netstat-n | awk '/^tcp/{++arr[$NF]}; End {to (k in arr) print K, "\ T", ar

1388个并发请求, this value Apache can be adjusted automatically according to the load condition.Netstat-nat|grep-i "|wc-l"#4341#netstat-an will print the current network link state of the system, and Grep-i "80" is used to extract connections related to port 80, wc-l count the number of connections.#最终返回的数字就是当前所有80端口的请求总数.Netstat-na|grep established|wc-l#376#netstat-an Prints the current network link state of the system, and grep established extracts the information that has been established for the

, trillion thorn?/p> -P Displays the name of the program that establishes the associated link-R Displays routing information, routing table-e display extended information, such as UID, etc.-S statistics according to each protocol-C executes the netstat command at every other fixed time. Hint: The status of listen and listening can only be seen with-a or-l Example First, view the number of connections for port 80 Netstat-nat|grep-i "|wc-l" Second, the number of connected IP to sort Netstat-

Linux DDOS and CC attack SolutionBackgroundNowadays, DDOS attacks are becoming more and more frequent. DDOS Denial-of-Service can be implemented without any technology. Some webmasters often report mysql 1040 errors on their websites, and their online users are less than one thousand, mysql configuration is fine. Generally, you need to pay attention to this situation. Your website may be attacked by CC attacks. Solutions and ideas CC attack defense measures, since the system is centos, run the f

: '{print $1}'|sort|uniq -c|sort -nr|head -n20netstat -ant |awk '/:80/{split($5,ip,":");++A[ip[1]]}END{for(i in A) print A,i}' |sort -rn|head -n20 3. Use tcpdump to sniff access to port 80 to see who is the highest tcpdump -i eth0 -tnn dst port 80 -c 1000 | awk -F"." '{print $1"."$2"."$3"."$4}' | sort | uniq -c | sort -nr |head -20 4. Search for more time_wait connections netstat -n|grep TIME_WAIT|awk '{print $5}'|sort|uniq -c|sort -rn|head -

'/^ tcp/{++ arr [$ NF]}; END {for (k in arr) print k, "\ t ", arr [k]} 'netstat-ant | awk' {print $ NF} '| grep-V' [a-z]' | sort | uniq-c # view port 80 connections up to 20 IPcat/www/web_logs /Waitalone.cn _ access. log | awk '{print $1}' | sort | uniq-c | sort-nr | head-100 tail-n 10000/www/web_logs/waitalone.cn _ access. log | awk '{print $1}' | sort | uniq-c | sort-nr | head-100cat/www/web_logs/waitalone.cn _ access. log | awk '{print $1}' | sort | uniq-c | sort-nr | head-100 netstat-anlp |

{16 int I;17 long result = 0;18 For (I = 1; I 19 {20 result + = I;(GDB) break 16 Breakpoint 1 at 0x8048496: file TST. C, line 16.(GDB) Break func Breakpoint 2 at 0x8048456: file TST. C, line 5.(GDB) info break Num type disp ENB address what1 breakpoint keep Y 0x08048496 in main at TST. C: 162 breakpoint keep Y 0x08048456 in func at TST. C: 5(GDB) r Starting program:/home/hchen/test/TST Breakpoint 1, main () at TST. C: 17 17 long result = 0;(GDB) n 18 For (I = 1; I (GDB)