java studdenly started failing

Yesterday webex started failing for me. I did not change anything related to java recently so I was a little perplexed.

Checking it turns out that even the standard test your java page failed. strace revealed the nice error:

$ grep ffff /tmp/TRA
6938  connect(22, {sa_family=AF_INET6, sin6_port=htons(80), inet_pton(AF_INET6, "::ffff:72.5.124.95", &sin6_addr), sin6_flowinfo=0, sin6_scope_id=0}, 28 <unfinished ...>
6938  connect(22, {sa_family=AF_INET6, sin6_port=htons(80), inet_pton(AF_INET6, "::ffff:72.5.124.95", &sin6_addr), sin6_flowinfo=0, sin6_scope_id=0}, 28) = -1 ENETUNREACH (Network is unreachable)

Notice that I don't have IPv6 connectivity!

Googling it turns out that you can disable IPv6 in java by modifying to ~/.java/deployment/deployment.properties the line:

deployment.javaws.jre.0.args=-Djava.net.preferIPv4Stack\=true

and all is now well. Until I need to access an IPv6 device with java of course :-(.