We make use of two cell providers in India, Airtel and Vodafone.
Airtel, where there is coverage, works as expected.
Vodafone gives us the following issues:
1. It can take upto 3 minutes for a connection to come up, so strongswan fails as the name lookup fails for our IPSec responder,
2. When the connection finally does come up, from another ssh console I can ping our IPSec responder but watching the log, using logread -f, I see strongswan trying to connect to the IPSec responder using an IPV6 address.
Why is it doing that? We have disabled IPV6 but nslookup is returning an IPv4 and IPV6 address for the responder.
We never have this issue with airtel.
Why is Vodafone doing this and how can we force strongswan to use only the IPV4 address?