VPN to dynamic address

I need to be able to use a Cisco 877 ADSL router to form a VPN tunnel to another on the end of an ADSL connection where I can't get a fixed IP address.

That remote site is using the dynDNS service

While the IOS config will accept a hostname instead of an IP address when I view the config it show as an Ip address. Therefore I assume it does a one-time DNS lookup and stores the IP address in the config.

Is there a way to get a Cisco device to accept a dynDns type name as the tunnel endpoint?

Reply to
Clive Carmock
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That's not possible.

Reply to
Lutz Donnerhacke

IOS will not accept a name however - never having done it - I would read up on DMVPN. I think that this will do the job but has various trade-offs.

Reply to
Bod43

Clive Carmock schrieb:

This is possible with a few restrictions by combining a wildcard preshared key with a dynamic lookup of the peer in the crypto map.

! crypto isakmp key insert-your-psk-here address 0.0.0.0 0.0.0.0 no-xauth crypto isakmp identity hostname ! crypto map cmap 10 ipsec-isakmp set peer yourdyndnssamplehost.dyndns.org dynamic !

The restrictions: no ipsec main mode, aggressive mode is used instead. You cannot use VTI or a routing protocol. If you have a fixed IP address on one side at least, setting up a DMVPN is much more convenient.

Reply to
Uli Link

see Cisco doc Configuring Router-to-Router Dynamic-to-Static IPSec with NAT

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Reply to
Merv

Clive Carmock schrieb:

You'll have to configure this as if the other end was a roving client: wildcard preshared key plus dynamic crypto map.

HTH T.

Reply to
Tilman Schmidt

In message , Uli Link writes

Thanks Uli - do you think this would work if both ends are Dynamically addressed? I assume I'd repeat this but in reverse at the other end?

Regards

Reply to
Clive Carmock

check out this new Cisco feature

Real-time Resolution for IPSec Tunnel Peer

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crypto map secure_b 10 ipsec-isakmp match address 140 set peer b.cisco.com dynamic

Reply to
Merv

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