[stunnel-users] stunnel 4.14 died silently under traffic stress test

[Zhuang Yuyao]

Hi,

While doing apache benchmark test, stunnel 4.14 died silently.

Network topo:
client(192.168.20.81 debian running ab2) ---(https)---> 
gateway(192.168.20.1 running stunnel in server mode) ---(http)---> web 
server(192.168.10.254)

Gateway hardware:
80386 compatible cpu (VIA C3 400Mhz);
RAM: 64M

stunnel.conf:
###############################
.....
compression = zlib
client = no
ciphers = DES-CBC3-SHA:DES-CBC3-MD5
verify = 1
[test]
accept = 443
connect = 192.168.10.254:80
TIMEOUTclose = 0
###############################

Web Server hardware:
Dell 2850 with 2G RAM.
test_100k.html is a html file whose size is 100k bytes.
test_4k.html is a html file whose size is 4k bytes.

In client, I am using ab2 as the stress test tool:
#ab2 -n 200 -c 100 https://192.168.20.1:443/test_4k.html (means 200 
request and 100 concurrency)
successfully finished.

#ab2 -n 200 -c 100 https://192.168.20.1:443/test_100k.html (means 200 
request and 100 concurrency)
stunnel died after a few seconds, running log shows:
2006.03.09 15:20:39 LOG5[6962:1024]: stunnel 4.14 on i386-pc-linux-gnu 
PTHREAD+POLL+IPv4 with OpenSSL 0.9.7i 14 Oct 2005
2006.03.09 15:20:39 LOG5[6962:1024]: 500 clients allowed
2006.03.09 15:20:53 LOG5[6964:1026]: test connected from 192.168.20.81:50186
2006.03.09 15:20:53 LOG5[6965:2051]: test connected from 192.168.20.81:50187
2006.03.09 15:20:53 LOG5[6966:3076]: test connected from 192.168.20.81:50188
2006.03.09 15:20:53 LOG5[6967:4101]: test connected from 192.168.20.81:50189
2006.03.09 15:20:53 LOG5[6968:5126]: test connected from 192.168.20.81:50190
2006.03.09 15:20:54 LOG5[6969:6151]: test connected from 192.168.20.81:50191
2006.03.09 15:20:54 LOG5[6970:7176]: test connected from 192.168.20.81:50192
2006.03.09 15:20:54 LOG5[6971:8201]: test connected from 192.168.20.81:50193
2006.03.09 15:20:54 LOG5[6972:9226]: test connected from 192.168.20.81:50194
2006.03.09 15:20:54 LOG5[6973:10251]: test connected from 
192.168.20.81:50195
2006.03.09 15:20:54 LOG5[6974:11276]: test connected from 
192.168.20.81:50196
2006.03.09 15:20:54 LOG5[6975:12301]: test connected from 
192.168.20.81:50197
2006.03.09 15:20:54 LOG5[6976:13326]: test connected from 
192.168.20.81:50198
2006.03.09 15:20:54 LOG5[6977:14351]: test connected from 
192.168.20.81:50199
2006.03.09 15:20:54 LOG5[6978:15376]: test connected from 
192.168.20.81:50200
2006.03.09 15:20:54 LOG5[6979:16401]: test connected from 
192.168.20.81:50201
2006.03.09 15:20:54 LOG5[6980:17426]: test connected from 
192.168.20.81:50202
2006.03.09 15:20:54 LOG5[6981:18451]: test connected from 
192.168.20.81:50203
2006.03.09 15:20:54 LOG5[6982:19476]: test connected from 
192.168.20.81:50204
2006.03.09 15:20:54 LOG5[6983:20501]: test connected from 
192.168.20.81:50205
2006.03.09 15:20:54 LOG5[6984:21526]: test connected from 
192.168.20.81:50206
2006.03.09 15:20:54 LOG5[6985:22551]: test connected from 
192.168.20.81:50207
2006.03.09 15:20:54 LOG5[6986:23576]: test connected from 
192.168.20.81:50208
2006.03.09 15:20:54 LOG5[6987:24601]: test connected from 
192.168.20.81:50209
2006.03.09 15:20:54 LOG5[6988:25626]: test connected from 
192.168.20.81:50210
2006.03.09 15:20:54 LOG5[6989:26651]: test connected from 
192.168.20.81:50211
2006.03.09 15:20:54 LOG5[6990:27676]: test connected from 
192.168.20.81:50212
2006.03.09 15:20:54 LOG5[6991:28701]: test connected from 
192.168.20.81:50213
2006.03.09 15:20:54 LOG5[6992:29726]: test connected from 
192.168.20.81:50214
2006.03.09 15:20:54 LOG5[6993:30751]: test connected from 
192.168.20.81:50215
2006.03.09 15:20:54 LOG5[6994:31776]: test connected from 
192.168.20.81:50216
2006.03.09 15:20:54 LOG5[6995:32801]: test connected from 
192.168.20.81:50217
2006.03.09 15:20:54 LOG5[6996:33826]: test connected from 
192.168.20.81:50218
2006.03.09 15:20:54 LOG5[6997:34851]: test connected from 
192.168.20.81:50219
2006.03.09 15:20:54 LOG5[6998:35876]: test connected from 
192.168.20.81:50220
2006.03.09 15:20:54 LOG5[6999:36901]: test connected from 
192.168.20.81:50221
2006.03.09 15:20:54 LOG5[7000:37926]: test connected from 
192.168.20.81:50222
2006.03.09 15:20:54 LOG5[7001:38951]: test connected from 
192.168.20.81:50223
2006.03.09 15:20:54 LOG5[7002:39976]: test connected from 
192.168.20.81:50224
2006.03.09 15:20:54 LOG5[7003:41001]: test connected from 
192.168.20.81:50225
2006.03.09 15:20:54 LOG5[7004:42026]: test connected from 
192.168.20.81:50226
2006.03.09 15:20:55 LOG5[7005:43051]: test connected from 
192.168.20.81:50227
2006.03.09 15:20:55 LOG5[7006:44076]: test connected from 
192.168.20.81:50228
2006.03.09 15:20:55 LOG5[7007:45101]: test connected from 
192.168.20.81:50229
2006.03.09 15:20:55 LOG5[7008:46126]: test connected from 
192.168.20.81:50230
2006.03.09 15:20:55 LOG5[7009:47151]: test connected from 
192.168.20.81:50231
2006.03.09 15:20:55 LOG5[7010:48176]: test connected from 
192.168.20.81:50232
2006.03.09 15:20:55 LOG5[7011:49201]: test connected from 
192.168.20.81:50233
2006.03.09 15:20:55 LOG5[7012:50226]: test connected from 
192.168.20.81:50234
2006.03.09 15:20:55 LOG5[7013:51251]: test connected from 
192.168.20.81:50235
2006.03.09 15:20:55 LOG5[7014:52276]: test connected from 
192.168.20.81:50236
2006.03.09 15:20:55 LOG5[7015:53301]: test connected from 
192.168.20.81:50237
2006.03.09 15:20:55 LOG5[7016:54326]: test connected from 
192.168.20.81:50238
2006.03.09 15:20:55 LOG5[7017:55351]: test connected from 
192.168.20.81:50239
2006.03.09 15:20:55 LOG5[7018:56376]: test connected from 
192.168.20.81:50240
2006.03.09 15:20:55 LOG5[7019:57401]: test connected from 
192.168.20.81:50241
2006.03.09 15:20:55 LOG5[7020:58426]: test connected from 
192.168.20.81:50242
2006.03.09 15:20:55 LOG5[7021:59451]: test connected from 
192.168.20.81:50243
2006.03.09 15:20:55 LOG5[7022:60476]: test connected from 
192.168.20.81:50244
2006.03.09 15:20:55 LOG5[7023:61501]: test connected from 
192.168.20.81:50245
2006.03.09 15:20:55 LOG5[7024:62526]: test connected from 
192.168.20.81:50246
Killed

It looks like that is resource on gateway is exhausted under such a 
traffic, but my question is: why stunnel just died instead of rejecting 
further connections.

Thanks very much.

Zhuang Yuyao