Router's external IP address

[Satanic Atheist]

Is it possible to discover the external IP address of a router on a masqueraded network from a Linux machine?

What I would like to do is play around with a mail server on a DynDNS hosted name. To be able to update DynDNS, I would need to know the external IP and whether it has changed.

Any ideas?

James

PS. The router is a LinkSys router, and if anyone knows if it supports DynDNS then please let me know. That would make things a lot easier since I could forward e-mail traffic straight through.

[ph34r]

Check out ddclient - updates dyndns automatically for you. One of the options in there is to get status from a router, or from an external website.

[Satanic Atheist]

Magic.

Thanks,

James