Some errors are quite common, and are often asked about on the mailing list. Chances are high that if you have a problem, it is listed in this section. Probably the most common and feared error is a variation of this one:
cannot respond to IPsec SA request because no connection is known for .....
This error message is usually the first error you will see for a lot of problems that can be encountered. It basically says, "The incoming IKE request does not match any of my loaded connections, I cannot respond to this IKE request." However, the reason behind the mismatch could be down to the local Openswan machine, but also it could be due to the remote machine. Read the line very carefully, and then read the connection definition in ipsec.conf
looking for any difference.
May 18 16:33:54 isi pluto[1917]: "west-l2tp-unpatched-windows-psk"[2] 69.196.174.6 #1: cannot respond to IPsec SA request because no connection is known for 193.110.157.131:17/1701...69.196.174.6[@testxp...