00002 add a timeout and disconnect if no input occurs
Created by: Pascal J. Bourguignon
Well for the cli too when we use it thru inetd…
Add a timeout and disconnect if no input occurs after that delay.
There seem to be scanners who connect to ports without sending anything, and keeping the ports open indefinitely. For example:
11:21:15.325617 IP 193.49.123.6.51872 > voyager.informatimago.com.8115: Flags [S], seq 1980334663, win 65535, options [mss 1460,nop,wscale 4,nop,nop,TS val 1368891875 ecr 0,sackOK,eol], length 0
E..@
'@./.nN.1{.X.>E....v .G.......................
Q...........
11:21:15.326556 IP voyager.informatimago.com.8115 > 193.49.123.6.51872: Flags [S.], seq 414189389, ack 1980334664, win 5792, options [mss 1460,sackOK,TS val 1403523590 ecr 1368891875,nop,wscale 7], length 0
E..<..@.@.gyX.>E.1{........Mv .H.....A.........
S...Q.......
11:21:15.416583 IP 193.49.123.6.51872 > voyager.informatimago.com.8115: Flags [.], ack 1, win 8235, options [nop,nop,TS val 1368891966 ecr 1403523590], length 0
E..4.2@./.~N.1{.X.>E....v .H...N.. +''.....
Q..>S...
11:21:18.160791 IP voyager.informatimago.com.8115 > 193.49.123.6.51872: Flags [P.], seq 1:257, ack 1, win 46, options [nop,nop,TS val 1403524299 ecr 1368891966], length 256
E..4.S@.@.Q.X.>E.1{........Nv .H...........
S...Q..>
[ENTREE] POUR ENTRER LES DONNEES.
[EFFACEMENT] POUR EFFACER LE CARACTERE PRECEDENT.
[CONTROLE-C] POUR INTERROMPRE.
(PAS DISPONIBLE) POUR ENVOYER LE SIGNAL D'ATTENTION (FONCTION ATT()).
[ENTREE] POUR ENTRER LES DONNEES, MAIS AJ
11:21:18.206093 IP 193.49.123.6.51872 > voyager.informatimago.com.8115: Flags [.], ack 257, win 8219, options [nop,nop,TS val 1368894740 ecr 1403524299], length 0
E..4+|@./.M..1{.X.>E....v .H...N.. ........
Q...S...
11:21:18.207059 IP voyager.informatimago.com.8115 > 193.49.123.6.51872: Flags [P.], seq 257:1640, ack 1, win 46, options [nop,nop,TS val 1403524310 ecr 1368894740], length 1383
E....T@.@.L.X.>E.1{........Nv .H....>......
S...Q...OUTE LE CODE RETOUR AUX CHAINES.
------------------------------------------------------------------------
\ OOO OOOOOOOOOO OOOOOOOOOO \
\ OOO OOOOOOOOOOOO OOOOOOOOOO OOOOOOOOOOO \
\ OOO OOOO OOO OOO \
\ OOO OOOO OOOOOO O OO \
> OOO OOOO OOOOOO OOO O O >
/......................................................................./
/ OOO OOO OOOO OOO OOOO OO OO /
/ OOOOOOOOOO OOO OOOOOOOOOOOO OOO OOOOOOOOOO OOO OOOO OO OO /
/ OOOOOOOOOO OOO OOOOOOOOOO OOO OOOOOOOOOO OOO O OOOO OO /
------------------------------------------------------------------------
NASIUM L.S.E.
LANGAGE SYMBOLIQUE D'ENSEIGNEMENT
VERSION 1.0.0-0.122-CCL-LINUX
COPYRIGHT 1984 - 2012 PASCAL BOURGUIGNON
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UTILISEZ LA COMMANDE DO LICENSE POUR PLUS DE DETAILS.
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BONJOUR 11:21:18
PRET
11:21:18.253022 IP 193.49.123.6.51872 > voyager.informatimago.com.8115: Flags [.], ack 1640, win 8133, options [nop,nop,TS val 1368894787 ecr 1403524310], length 0
......Q.....
Q..CS...
voyager:/home/lse# netstat -tnp|grep 8115
tcp 0 0 88.198.62.69:8115 62.23.193.34:31565 ESTABLISHED 24512/lse
tcp 0 0 88.198.62.69:8115 92.140.3.120:50785 ESTABLISHED 17970/lse
tcp 0 0 88.198.62.69:8115 90.24.180.197:57483 ESTABLISHED 28317/lse
tcp 0 0 88.198.62.69:8115 193.49.123.6:51872 ESTABLISHED 11342/lse
tcp 0 0 88.198.62.69:8115 90.46.107.24:60060 ESTABLISHED 14863/lse
tcp 0 0 88.198.62.69:8115 82.123.216.50:54617 ESTABLISHED 8319/lse
tcp 0 0 88.198.62.69:8115 90.46.43.101:65094 ESTABLISHED 3108/lse
tcp 0 0 88.198.62.69:8115 92.163.83.173:57699 ESTABLISHED 31147/lse
tcp 0 0 88.198.62.69:8115 90.24.196.163:49181 ESTABLISHED 8555/lse
tcp 0 0 88.198.62.69:8115 92.140.0.205:53295 ESTABLISHED 18925/lse
tcp 0 0 88.198.62.69:8115 82.123.168.209:51062 ESTABLISHED 21410/lse
tcp 0 0 88.198.62.69:8115 109.190.38.230:49716 ESTABLISHED 12126/lse
tcp 0 0 88.198.62.69:8115 92.163.81.111:62166 ESTABLISHED 25565/lse