Trying to use IPv6 on a non-IPv6 network stops connection

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Run ConnectBot when connected to a non-IPv6 enabled network
2. Connect to a host with IPv6 (AAAA record) set in DNS as well as IPv4

What is the expected output? 
- It should connect as per normal over IPv4

What do you see instead?
- It sits there trying to connect forever without any success

What version of the product are you using?
- ConnectBot 1.7.1

What type of system are you trying to connect to?
- Ubuntu & Debian linux servers (bilbo.valorin.net & rowlf.valorin.net)

Let me know if you need any other information.

Original issue reported on code.google.com by step...@rees-carter.net on 10 Oct 2010 at 8:12

[GoogleCodeExporter]

I have seen similar behavior, except instead of trying to connect forever, the 
connection times out and I get the "Host has disconnected. Close Session? 
Yes/No" question.

Original comment by douglaswth on 1 Jan 2011 at 12:38

[GoogleCodeExporter]

Hi,

could the bug poster please elaborate "forever without any success"?

While switching from a v6-enabled network to a v4-only network ConnectBot 
usually gets a "Network unreachable".
This is the case when connecting to a v6-enabled WiFi, doing SSH via v6 and 
disconnecting from said WiFi. ConnectBot then drops the connection as expected.
After trying to reconnect it fails with "Network unreachable" (address/route 
over WiFi had been removed). Nevertheless ConnectBot cached the AAAA address 
and will not try to do an A-RR lookup until it is killed and started again.

Original comment by eim...@etherkiller.de on 31 Jan 2011 at 4:47

[GoogleCodeExporter]

"forever without any success" - Connectbot looks up the DNS name of the target 
hosts and gets both the IPv4 & IPv6 address as response. It then tries to 
connect to the IPv6 address but if there's no IPv6 connectivity present (i.e. 
no v6 routes), Connectbot fails to connect and will eventually time out.

Original comment by ckujau on 29 Dec 2014 at 11:54