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Re: IOS 12.3(x) Strange service ports open on router
On 9-apr-04, at 22:27, Pekka Savola wrote:
Another pet peeve of roughly the same category: when you enable IPv6, telnet is automatically open to the world (using v6), even if you have disabled v4 telnet with an access-list.
Whether or not this is a problem is in the eye of the beholder, but from what I've seen, this is standard practice with any kind of packet filter. As far as I know, only hosts.allow-style tcp wrapping is agnostic about the IP version.The vendor refused to believe this is a problem,
If you want to run a new protocol, you have to configure filters for it unless you want to go through life unfiltered. That's the way things work.
It's even worse with FreeBSD: if you firewall it to the teeth in v4 and disable v6 in the rc.conf, it will still run v6 with link-local addresses and allow access to the services that are filtered in v4.