- NZNOG - lists.nznog.org

Re: [nznog] SMTP Servers and Reverse DNS Lookup
by Juha Saarinen 14 Jun '04

14 Jun '04

neil gardner wrote: > Um, no false positives? doesn't that mean you manually inspect all your > logs of dropped connections? Doesn't, by extension, that mean you might > as well let all the stuff through and check them at the client end? :-) Yes, I do check the logs, which is a lot easier than it may appear. No, it doesn't mean I might as well let the stuff through... -- Juha

1 0

Re: [nznog] SMTP Servers and Reverse DNS Lookup
by neil gardner 14 Jun '04

14 Jun '04

Um, no false positives? doesn't that mean you manually inspect all your logs of dropped connections? Doesn't, by extension, that mean you might as well let all the stuff through and check them at the client end? :-) Cheers - N >>> Juha Saarinen <juha(a)saarinen.org> 15/06/2004 3:30:14 p.m. >>> neil gardner wrote: > http://www.cs.niu.edu/~rickert/cf/bad-ehlo.html > > Decent understandable writeup of the "You should send the right info" > and "Don't drop email if you get the wrong info" arguments... ... and having said all that, I admit to dropping some some messages based on HELOs. Mainly viruses and spamware connections, with no false positives yet. Touch wood. -- Juha NOTICE: This message contains privileged and confidential information intended only for the use of the addressee named above. If you are not the intended recipient of this message you are hereby notified that you must not disseminate, copy or take any action in reliance on it. If you have received this message in error please notify Allied Telesyn Research Ltd immediately. Any views expressed in this message are those of the individual sender, except where the sender has the authority to issue and specifically states them to be the views of Allied Telesyn Research.

2 1

Re: [nznog] SMTP Servers and Reverse DNS Lookup
by neil gardner 14 Jun '04

14 Jun '04

http://www.cs.niu.edu/~rickert/cf/bad-ehlo.html Decent understandable writeup of the "You should send the right info" and "Don't drop email if you get the wrong info" arguments... Cheers - N. >>> Juha Saarinen <juha(a)saarinen.org> 15/06/2004 2:56:14 p.m. >>> Regan Murphy wrote: > Is this sort of configuration becoming standard for organistions? Some admins think it's BOFH to do stuff like that, in the mistaken belief that it's RFC-compliant. It's a bit like fundamentalists interpreting various religious scriptures, but if they want to drop legitimate email, their choice I say. -- Juha _______________________________________________ NZNOG mailing list NZNOG(a)list.waikato.ac.nz http://list.waikato.ac.nz/mailman/listinfo/nznog NOTICE: This message contains privileged and confidential information intended only for the use of the addressee named above. If you are not the intended recipient of this message you are hereby notified that you must not disseminate, copy or take any action in reliance on it. If you have received this message in error please notify Allied Telesyn Research Ltd immediately. Any views expressed in this message are those of the individual sender, except where the sender has the authority to issue and specifically states them to be the views of Allied Telesyn Research.

2 1

SMTP Servers and Reverse DNS Lookup
by Regan Murphy 14 Jun '04

14 Jun '04

I was having problems sending mail to an organisation and eventually worked out that the host name and reverse dns entry did not match and therefore mail transfer was refused: ------- 220 mail.xxxbar.co.nz ESMTP NetIQ MailMarshal (v5.5.5.8) Ready ehlo hellmouth.oaxxxsystems.co.nz 554 No SMTP service here ------- As soon as I corrected my server to use the correct host name to match the reverse (vampire.oaxxxsystems.co.nz) then mail was allowed to go through. I would assume this was a recent change by the receiving organisation as I have not had problems sending them emails before. Is this sort of configuration becoming standard for organistions? I would expect that may create problems for smaller organisations sending email directly from their in-house hosted mail server for which they have no control over reverse-dns entries. -- Regards, Regan

5 5

RE: [nznog] TelstraClear Inhternational / National Traffic billing
by Craig Spiers 14 Jun '04

14 Jun '04

Well.. You could get a link to both, but the only real benefit would be splitting the cost between two (probably slightly more expensive this way as a separate circuit is needed for both - generally cheaper to upgrade a 10meg to 100meg than it is to install 2x 10meg eg. one from each telco) However, you would have a shorter data path.. As with two circuits, the data goes direct to both carriers.. With just one circuit, data to clear, goes via telecom.. (provided they keep the peering between them). -----Original Message----- From: jfp [mailto:jfp(a)clearfield.com] Sent: Tuesday, 15 June 2004 12:16 p.m. To: 'Craig Spiers' Subject: RE: [nznog] TelstraClear Inhternational / National Traffic billing > They shouldn't be connected to the internet at all! They should be > shot in the foot for having such poor routing :) > > NZ > US > NZ :) Not being in the ISP business, but a client of ISP's, could you explain that one to me. I thought the whole point of peering at the APE and WIX was that you did not need to get point to point link to other providers. Why do you NEED to get a link to one of the telco's? jfp. ------------------------------------------------------------------------ Jean-Francois Pirus <jfp(a)clearfield.com> Clearfield Software Ltd Phone (+64-9) 358 2081 4th Floor 8-10 Whitaker Place Fax (+64-9) 358 2083 P O Box 2348 Auckland, New Zealand ------------------------------------------------------------------------

1 0

Re: Map/schematic over NZ Internet connectivity?
by Kerry Milestone 13 Jun '04

13 Jun '04

The National Library of New Zealand has been given a lot! of money, i expect they will have a good map soon......... http://www.beehive.govt.nz/ViewDocument.cfm?DocumentID=19882 And an older National Business Review article: http://www.nbr.co.nz/home/column_article.asp?id=1978&cid=1&cname=Media Maybe some of it can be spent on peering networks together to help with the flow of _all_ websites ending in .nz to be harvested daily by the NatLib... This task is now part of the National Library Bill and can be thought of being the same as the Legal Deposit legislation.

1 0

xtra's MTA again??
by Dan Clark 13 Jun '04

13 Jun '04

Hi Guys, just wondering if anyone else isn't getting any mail through to XTRA. If you are and your mta is MailMarshal please let me know also, from last time there appeared to be an issue with MailMarshal threads. Kind Regards Dan Clark Network Manager Synaptic Ltd

4 3

RE: Map/schematic over NZ Internet connectivity?
by Brendan Murray 12 Jun '04

12 Jun '04

> Message: 3 > Date: Sun, 13 Jun 2004 11:26:20 +1200 > From: Juha Saarinen <juha(a)saarinen.org> > Subject: Re: [nznog] Map/schematic over NZ Internet connectivity? > To: jon.brewer(a)worldnet.att.net > Cc: 'NZ NOG' <nznog(a)list.waikato.ac.nz> > Message-ID: <40CB911C.3010600(a)saarinen.org> > Content-Type: text/plain; charset=us-ascii; format=flowed > > Jonathan Brewer wrote: > > > I tried InternetNZ with this very question about a year ago, and the > > answer was no. > > I guess there was no follow-up along the lines of "... but we're working > on it"? Give me good/adequate/useful/whatever reasons for doing it and I'll take it to the INZ tech committee. Always nice to add things to the ToDo list. More usefully - others on this list probably already have some/all of a map - where can we access that information if INZ does decide its worth putting together? And how do we keep it up to date?

2 1

Re: [nznog] Zombies
by Ewen McNeill 10 Jun '04

10 Jun '04

In message <20040610051613.GJ20881(a)stateless>, Nicholas Lee writes: >On Thu, Jun 10, 2004 at 04:58:31PM +1200, Ewen McNeill wrote: >> [... suggesting] anti-spam legislation, a legal duty be placed on people >> not to connect/allow to remain connected an insecure/0wned/infected >> system under their control. > >Unlike vehicles, access to the internet for most people is not via a >"public road". [...] >A WOF/license for driving the internet just seems like needless legisation. I actually didn't suggest a WOF/license for driving on the Internet (this time -- although I do actually think it's a good idea). What I suggested was that those who have allowed systems they own to become unsafe/damaged so that they cause harm to others should be made responsible for that harm. And it doesn't seem like needless legislation to me. It's not _my_ systems (or any of the ones I'm responsible for administering) which are sending thousands of spam messages, viruses, worms, to machines across the world. I just get to receive thousands of them a day via all these machines of people who are not taking responisbility for the systems they're connecting to a common resource (viz, the Internet). As Juha says there is a problem with patches not being available. I'd be quite happy to allow "no vendor patch" as a complete defense for the end user (although if the issue is well known the vendor should perhaps be culpable). I'd even be willing to conceed "vendor patch too recently released, couldn't patch everything" with in a reasonable amount of time of the patch coming out. Simply persuading someone to take responsibility for the never-been-patched, installed-stuff-at-random, insecure-OS-design boxes would dramatically reduce the problem. >ISPs already have the power to regulate users this way via their TOS. Its >clear though that all ISPs would have to subscribe to the above for it >to have long-term effect. The days of ISPs taking responsibility for the actions of their users appear to be a fading memory. It's unlikely any ISP would block users with infected machines these days unless all ISPs did it; the only way that all ISPs are likely to do it is if it's a legal requirement. (Otherwise it's a prisoner's dilemma situation.) Ewen

7 6

Re: [nznog] Zombies
by neil gardner 10 Jun '04

10 Jun '04

OK, serious thought here... Bear with me... I may be a) Describing an existing system or b) way off base. Transparent SMTP proxy intercepts all messages and maintains a running total of emails sent per source IP. This running total is actually stored as a time distribution (ie. 10 emails in 10 minutes, then none in 10, then 100 in ten etc) Rulebase periodically examines this time distribution for each source IP. Something like If last 3 matches are >10, >10, >10 then block for 30 minutes per strikeout(sourceIP) and increment strikeout(sourceIP) by one. After expiry of downtime, open them up again. After (say) 90 minutes of non-abhorrent behaviour, decrement strikeout(sourceip) by one. If strikeout(sourceIP) gets to threshold (Say 10) then email user and 48 hours later disable account unless they contact helpdesk and claim to have addressed the situation. You probably want cleverer rules to identify bursts of email, and possibly a training period with rules referrent to earlier data from the same source - this should be able to reliably identify legitimate high volume users - especially if you build in a time of day factor. This should quickly throttle zombies and disable the account if not fixed, but allow for brief infections to be throttled, and if fixed, NOT need manual intervention to unblock. It may impact some legit heavy email users, but mail will bounce, and it should fix itself. Just a thought. Cheers - N. >>> Simon Lyall <simon(a)darkmere.gen.nz> 10/06/2004 1:46:38 p.m. >>> It looks like there are lot of NZ based Zombies sending very large amounts of Spam ( much of it in German) to some ISPs. This has really been going hard over the last hour. I'm seeing adsl accounts at xtra, iprolink and ihug, xtra dialups etc etc. As a related issue, how do people feel about a whitelist RBL of NZ mail servers, It looks like it's not good to just whitelist NZ IPs -- Simon J. Lyall. | Very Busy | Mail: simon(a)darkmere.gen.nz "To stay awake all night adds a day to your life" - Stilgar | eMT. _______________________________________________ NZNOG mailing list NZNOG(a)list.waikato.ac.nz http://list.waikato.ac.nz/mailman/listinfo/nznog NOTICE: This message contains privileged and confidential information intended only for the use of the addressee named above. If you are not the intended recipient of this message you are hereby notified that you must not disseminate, copy or take any action in reliance on it. If you have received this message in error please notify Allied Telesyn Research Ltd immediately. Any views expressed in this message are those of the individual sender, except where the sender has the authority to issue and specifically states them to be the views of Allied Telesyn Research.

6 7