My linode has 2 IP addresses, and matching reverse DNS entries.

Can the outside net determine that these two IPs are on the same machine?

In particular, can webcrawlers and SMTP clients make such an identification?

If so, what commands can I run to see that myself?

I ask because I am interested in setting up a mailing list server separate from my main site, so as not to risk the spam rating of the main site. Is it necessary for these services to be split on completely different machines?

Thanks!

Chris

Not really as far as I know. Given the 2 IP's they will know that they both are on linodes and both are in the same datacenter. If you have reverse DNS set up right (and you probably will if they're sending email), then they could look at registrations for DNS and guess. That's it though.



You shouldn't worry about that at all. I'd be much more worried about neighbors on your netblock spamming which can get the whole network on blacklists.

OK, thanks for the quick answer.

The only thing they can find out is that linode owns both ips

OK, that is great to know. Thanks for that!

Chris

False!!!!!

ssh-keyscan is your friend....

That of course assumes you have ssh running on both addresses which is easy to fix..

_________________
ServerAdmin - www.our-lan.com
"Diplomacy is the art of saying nice doggy whilst looking for a really big stick"
"In my experiece, any attempt to make any system idiot proof will only challenge God to make a better idiot"

Yeah, there are a lot of ways depending on what services you have running and configuration of those services. For instance, most mail servers will by default attach to all IPs and it give out your real hostname.