GetMyExternalIP() why, and what happens if down ?

[Nicolas Dorier]

I see that GetMyExternalIp() is hard coded to query www.showmyip.com and checkip.dyndns.org to get the IP of the bitcoin node.

Now there is two things I don't understand :

Why doing that ?
A recieving Bitcoin node could easily use the IP packet to get the IP of the sender, instead of that, it seems to rely on the addr_from of the Version message payload.

And what happens if both showmyip and checkip dyndns are down ? (At my home showmyip does not work)
Does most of the miners will be unable to communicate leading to a bitcoin apocalypse ?

Second, out of topic, how can I remove this ******* time limit that say I can't post on this forum because I already did it just before altough it is not true.

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[tholenst]

See https://github.com/bitcoin/bitcoin/pull/3461 and https://github.com/bitcoin/bitcoin/pull/3088 for work on changing this.

[gmaxwell]

Very little happens at all if it doesn't work. It's only used for hosts which are behind nat, which don't use UPNP to learn their address, and which don't have a manually configured address. These addresses are only used for announcing to other peers what addresses they can connect to.