{"id":2121,"date":"2015-04-06T19:07:23","date_gmt":"2015-04-06T19:07:23","guid":{"rendered":"https:\/\/qbytes.cloud\/?p=2121"},"modified":"2015-04-06T19:07:23","modified_gmt":"2015-04-06T19:07:23","slug":"netstat-commands-for-ddos-checking","status":"publish","type":"post","link":"https:\/\/www.qbytes.cloud\/index.php\/2015\/04\/06\/netstat-commands-for-ddos-checking\/","title":{"rendered":"Netstat Commands for DDoS Checking"},"content":{"rendered":"

Useful commands to check if a server is getting ddos’d<\/p>\n

Show IPs with more than 10 connections open:<\/p>\n

\n\n# netstat -nat | grep ":80" | awk -F: '{print $8}' | sort | uniq -c | sort -n | awk '{ if ( $1 > 10) print $2 ; }'\n\n<\/pre>\n
Show # of connections open per IP<\/p>\n
\n\n# netstat -nat | egrep ":80|:443" | awk -F: '{print $8}' | sort | uniq -c | sort -n \n\n<\/pre>\n
Number of connections per IP<\/p>\n
\n\n# netstat -anp |grep 'tcp\\|udp' | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -n\n\n<\/pre>\n
Haynie’s version(better sorting):<\/p>\n
\n\n# netstat -anp|awk '{print $5}'|awk -F: '{print $4}'|sort -n -t. -k1,1 -k2,2 -k3,3 -k4,4|uniq -c|sort -n\n\n<\/pre>\n
Drop ips with 100 or more connections:<\/p>\n
\n\n# netstat -nat | egrep ":80|:443" | awk -F: '{print $8}' | sort | uniq -c | sort -n | awk '{ if ( $1 > 100) print $2 ; }' | xargs -n1 echo iptables -I INPUT -j DROP -s\n\n<\/pre>\n
Graphic netstat connections(# of connections open per host)<\/p>\n
# netstat -an | grep ESTABLISHED | awk ‘{print $5}’ | awk -F: ‘{print $1}’ | sort | uniq -c | awk ‘{ printf(“%s\\t%s\\t”,$2,$1) ; for (i = 0; i < $1; i++) {printf(\"*\")}; print \"\" }'\n\n[\/bash]\n<\/p>\n","protected":false},"excerpt":{"rendered":"
Useful commands to check if a server is getting ddos’d Show IPs with more than 10 connections open: # netstat -nat | grep ":80" | awk -F: '{print $8}' | sort | uniq -c | sort -n | awk '{ if ( $1 > 10) print $2 ; }' Show # of connections open per … Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[72],"tags":[],"class_list":["post-2121","post","type-post","status-publish","format-standard","hentry","category-networking"],"_links":{"self":[{"href":"https:\/\/www.qbytes.cloud\/index.php\/wp-json\/wp\/v2\/posts\/2121","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.qbytes.cloud\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.qbytes.cloud\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.qbytes.cloud\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.qbytes.cloud\/index.php\/wp-json\/wp\/v2\/comments?post=2121"}],"version-history":[{"count":0,"href":"https:\/\/www.qbytes.cloud\/index.php\/wp-json\/wp\/v2\/posts\/2121\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.qbytes.cloud\/index.php\/wp-json\/wp\/v2\/media?parent=2121"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.qbytes.cloud\/index.php\/wp-json\/wp\/v2\/categories?post=2121"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.qbytes.cloud\/index.php\/wp-json\/wp\/v2\/tags?post=2121"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}