I'm running Windows 7 64-bit. After installing Java 7 (part of PS3 media server) when I was previously using Java 6, my Eclipse (Indigo Service Release 2, Build id: 20120216-1857) CVS stopped working to the server that's on a VPN. I connect using Cisco AnyConnect VPN Client Version 2.5.2019. The error I get whenever I try to connect to a repository is the following:
Could not connect to :extssh:username@example.com:/cvsroot/username/project: CVS communication error: org.eclipse.team.internal.ccvs.ssh2.CVSSSH2ServerConnection$SSH2IOException: Permission denied: connect
Permission denied: connect
I'm able to work around it by forcing Eclipse to run under the Java 6 JVM. It's not a firewall issue, because I turned off the Windows firewall, and also Wireshark shows no traffic beyond the DNS lookup.
Both my JREs (Java 6 and Java 7) are 32-bit versions; their paths are respectively
C:\Program Files (x86)\Java\jre6
C:\Program Files (x86)\Java\jre7
I found an answer that is to a very similar question, except it involves SVN rather than CVS. The "bug" seems to be that Cisco AnyConnect VPN is not supporting properly IPv6, which is invoked with the newer jre7.
So, adding the following to my eclipse.ini is a fix for my situation:
openFile
-vmargs
-Djava.net.preferIPv4Stack=true
来源：https://stackoverflow.com/questions/10270339/eclipse-cvs-extssh-broken-under-windows-7-java-7