[libtorrent] external_ip_alert

[Michael Mckeown]

Hi,

external_ip_alert used to when the session was first started pop an
alert for the ipv4 connection then pretty much straight away an alert
for the ipv6 connection (if any) then as time went on in the session you
would get alerts each time the ip changed (turning on a VPN, going from
WiFi to wired) but now when the session is first started you might get
an alert to know the ipv4 and likely won't get the follow up ipv6 alert
and likely won't get any alerts caused through adapter changes.

I'm not really seeing anything depreciated in the change-log that would
stop external_ip_alert functioning as it did, anyway do you think this
could be restored to it's former behavior as I think it's better to have
LibTorrent tell you when it's IP has changed rather than the client
monitor things instead.

Thanks.

[Arvid Norberg]

Post by Michael Mckeown
Hi,
external_ip_alert used to when the session was first started pop an
alert for the ipv4 connection then pretty much straight away an alert
for the ipv6 connection (if any) then as time went on in the session you
would get alerts each time the ip changed (turning on a VPN, going from
WiFi to wired) but now when the session is first started you might get
an alert to know the ipv4 and likely won't get the follow up ipv6 alert
and likely won't get any alerts caused through adapter changes.
I'm not really seeing anything depreciated in the change-log that would
stop external_ip_alert functioning as it did, anyway do you think this
could be restored to it's former behavior as I think it's better to have
LibTorrent tell you when it's IP has changed rather than the client
monitor things instead.

that alert will only be posted when libtorrent (with some degree of
certainty) learns about the external IP. This is done by collecting "votes"
of what the external IP might be from various sources, such as:

1. DHT peers (but not all peers will tell you)
2. bittorrent peers (but not all of them will tell you)
3. a NAT-PMP router (if there is one)
4. a tracker response (but not all trackers tell you)

Once enough samples are collected the external IP is determined and posted
as an alert.

For example, if you don't have any torrents and have the DHT and NAT-PMP
disabled, you won't get any external IP alert.