Linux Web Server site Failure Analysis common commands

System Network Connection Status:

1. View TCP connection Status

Netstat-nat |awk ' {print $6} ' |sort|uniq-c|sort-rnnetstat-n | awk '/^tcp/{++s[$NF]}; END {for (a in S) print A, s[a]} ' or Netstat-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 |awk '/^tcp/{print $NF} ' |sort|uniq-c|sort-rnnetstat-ant | awk ' {print $NF} ' | Grep-v ' [A-z] | Sort | Uniq-c

2. Find the number of requests 20 IP (commonly used to find the source of attack):

Netstat-anlp|grep 80|grep Tcp|awk ' {print $} ' |awk-f: ' {print '} ' |sort|uniq-c|sort-nr|head-n20netstat-ant |awk '/:8 0/{split ($5,ip, ":"); ++a[ip[1]]}end{for (i in A) print A[i],i} ' |sort-rn|head-n20

3. Sniff 80-port access with tcpdump to see who is the tallest

Tcpdump-i ETH0-TNN DST Port 80-c 1000 | Awk-f "." ' {print $ '. $ "." $ "." $4} ' | Sort | uniq-c | Sort-nr |head-20

4. Find more time_wait connections

Netstat-n|grep Time_wait|awk ' {print $} ' |sort|uniq-c|sort-rn|head-n20

5. Check for more SYN connections

Netstat-an | grep SYN | awk ' {print $} ' | Awk-f: ' {print $} ' | Sort | uniq-c | Sort-nr | More

6. Depending on the port column process

NETSTAT-NTLP | grep 80 | awk ' {print $7} ' | Cut-d/-F1

Website Log analysis (Apache):

1. Get access to the top 10 IP addresses

Cat Access.log|awk ' {print $} ' |sort|uniq-c|sort-nr|head-10cat Access.log|awk ' {counts[$ (11)]+=1}; END {for (URL in counts) print Counts[url], url} '

2. Most visited files or pages, take the top 20

Cat Access.log|awk ' {print $11} ' |sort|uniq-c|sort-nr|head-20

3. List the maximum number of EXE files to be transmitted (commonly used when analyzing the download station)

Cat Access.log |awk ' ($7~/.exe/) {print $ "" $ "" $4 "" $7} ' |sort-nr|head-20

4. list exe files with output greater than 200000byte (approx. 200kb) and the number of corresponding file occurrences

Cat Access.log |awk ' ($ > 200000 && $7~/.exe/) {print $7} ' |sort-n|uniq-c|sort-nr|head-100

5. If the last column of the log records the paging file transfer time, there are the most time-consuming pages listed to the client

Cat Access.log |awk ' ($7~/.php/) {print $NF "" $ "" $4 "" $7} ' |sort-nr|head-100

6. List the most time-consuming pages (more than 60 seconds) and the number of corresponding page occurrences

Cat Access.log |awk ' ($NF > && $7~/.php/) {print $7} ' |sort-n|uniq-c|sort-nr|head-100

7. List files that have been transmitted for longer than 30 seconds

Cat Access.log |awk ' ($NF >) {print $7} ' |sort-n|uniq-c|sort-nr|head-20

8. Statistics website Traffic (G)

Cat Access.log |awk ' {sum+=$10} END {print sum/1024/1024/1024} '

9. Statistics 404 of the Connection

awk ' ($9 ~/404/) ' Access.log | awk ' {print $9,$7} ' | Sort

10. Statistics HTTP Status

Cat Access.log |awk ' {counts[$ (9)]+=1}; END {for (code in counts) print code, Counts[code]} ' cat Access.log |awk ' {print $9} ' |sort|uniq-c|sort-rn

10. Spider analysis to see which spiders are crawling content.

/usr/sbin/tcpdump-i Eth0-l-S 0-w-DST Port 80 | Strings | Grep-i User-agent | Grep-i-E ' bot|crawler|slurp|spider '

Website Log Analysis 2 (SQUID) statistic traffic by domain

Zcat squid_access.log.tar.gz| awk ' {print $10,$7} ' |awk ' begin{fs= "[/]"}{trfc[$4]+=$1}end{for (domain in TRFC) {printf "%st%dn", Domain,trfc[domain]}} ‘

Database:

1. View SQL executed by the database

/usr/sbin/tcpdump-i eth0-s 0-l-w-dst Port 3306 | Strings | Egrep-i ' select| update| delete| Insert| Set| Commit| rollback| create| drop| alter| Call '

System Debug Analysis:

1. Debug commands

Strace-p PID

2. Tracking the PID of the specified process

Gdb-p PID

Linux Web Server site Failure Analysis common commands