nanog mailing list archives

RE: RBL-type BGP service for known rogue networks?


From: "Roeland M.J. Meyer" <rmeyer () mhsc com>
Date: Sun, 9 Jul 2000 08:22:46 -0700


I could list a number of sites, (northgrumm.com et al
AeroSpace/DOD clients) where the first step, in security, is to
block port 22. In fact, to block ALL encrypted traffic. Those
guys see that as a National Security and contract requirements
issue <grin>. Those same outfits ban radio xmit/rcv at the guard
shack<g>.

For other, more civilian organizations, we frequently work with
groups that have SA staff that considers that the first step in
security is to cut the connection altogether. Failing that,
blocking all ports, on all hosts, is the next reflexive step.
Eventually, we get down to required ports and proxy servers. The
bottom-line is that we've had to go as far as running a VPN on
port 80 and that only works if there is a direct path (no proxy).
In many organizations, a system isn't considered secure unless
port 22 is blocked, at the firewall. It is, after all, the secure
port, that must mean that you have to block it to be secure,
right?

In this sort of environment, we don't usually get assigned
internal email accounts, we have to use our own. However, they
usually allow proxied port 25 and 110 access but the source
address is still theirs. Yes, I already use F-Secure when I can.

From: Dana Hudes: Saturday, July 08, 2000 9:55 PM

The solution is not to open relays but to use an IPSEC tunnel
into the internal network. Or you could use SSH port
forwarding to accomplish the same thing.
If you open relays, the spammers will find and abuse them.
IPSEC clients and servers are available commercially. Nortel
Networks Contivity Extranet Gateway is one, and Nortel use it
themselves.
Shiva have a similar product.


From: "Roeland M.J. Meyer" <rmeyer () mhsc com>
Sent: Sunday, July 09, 2000 12:24 AM

Roland (first off, you're missing an 'e' <g>),

I agree. MHSC lost an entire market plan, hosting third-party
secure mail, becasue third-party mail services must allow
relaying that is at minimum semi-open. At the time SMTP AUTH
didn't exist (Until it's use becomes more wide-spread it
still
isn't real useful). The anti-relay bunch are killing a valid
business model. Even for internal use, we have staff, on
client-site, that need to send/recieve their mail from our
servers, even when their lap-top is DHCP attached to another
net-block. Every week we find ourselves having to open the
relays
more and more. Next week, I am travelling to the EU on
business.
That's yet more net-blocks that I have to allow relaying
from.

A single ORBS forged header, with the right source info in
it,
will pass right through our mail system, like it was greased.
The
whole anti-relay jihad is a fallacious rat-hole populated by
rabid self-righteous rats who don't have a clue. If they
don't
need it then it must not be a valid feature <humph!>. ORBS
itself
should be RBL'd, IMHO.

Using the same sort of mind-set to subjectively BL
script-kiddee
networks is dangerous, as the ORBS bunch has shown. It is all
too
easy for it to get out of hand, vigilante-style. What are the
criteria and who has the over-sight?

That said, having had a few of our production hosts "owned",
by
mwsh in the past, I am NOT fond of script-kiddies and agree
that
something needs to be done. But, I am seriously resistant to
yet
another ORBS style regulator bunch. That is NOT the answer.
Please, let's all look for another solution.

---
R O E L A N D  M .  J .  M E Y E R
CEO, Morgan Hill Software Company, Inc.
Tel: (925)373-3954
Fax: (925)373-9781
http://staff.mhsc.com/rmeyer



rdobbins () netmore net: Saturday, July 08, 2000 11:03 AM

ORBS forge headers (thereby violating the RFC) to look as
if
they're coming
from domains you host, then if it goes through, they put
you
in their little
black book for being an 'open relay'.  No notice, nothing.

The problem with this is that for hosting-only providers
like
my firm, it's
blatantly unfair.  We have thousands of users residing on
networks (lots of

encourage them to use IMAP, it's like herding cats to get
any
substantial
percentage doing anything other than basic POP and SMTP.

POP-before-SMTP isn't viable for the same reason that it's
extremely
difficult to get people to use IMAP; to wit, users tend to
resist change.
In a corporate environment, you can force remote users to
use
additional
authentication mechanisms, as long as you're willing to set
them up and
train the users.  Out here in the world, though, if you
come
down on people
over something which forces them to change the way they do
things in any
substantial way, they vote with their feet and go to some
other provider who
not only doesn't secure his mail relay, but ignores spam
complaints, as
well.






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