January 2000 - Test - lists.nanog.org

Mail problems, not microsoft
by Sean Donelan 03 Jan '00

03 Jan '00

On Sun, 02 January 2000, Owen DeLong wrote: > I don't even assume that anyone elses mail system works, let > alone that it works this way, or even complies with the RFC's. > > There's way too much MicroSoft stuff out there to believe > any of that. I merely purport that the above is BCP. Actually I haven't heard of any Microsoft mail problems in the last two days. Almost all the problems have been with old UNIX mailers putting "100" as the year on messages.

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Re: mail does bounce (was: Customers down?)
by sthaug＠nethelp.no 03 Jan '00

03 Jan '00

> > I know for certain that Postfix and Smail will immediately bounce a > > message when the domain is authoritatively non-existant. I'd be very > > surprised and dismayed if sendmail and all other true SMTP mailers did > > not do exactly the same thing. > > Sendmail most definitely does not, instead treating the error as a > transient error, issuing an SMTP error code in the 400 series, and > continuing to try to send the mail for up to five days (the default), > or whatever the mail server admin configured for that particular > server. > > I think I like it better that way. Just because both nameservers are > temporarily down doesn't mean the domain doesn't exist. :P Seems to me you're talking past one another. If all nameservers for a domain are down there *is* no nameserver which can say that the domain is authoritatively non-existent. (OK, you could get a negative caching answer from one of the authoritative servers on the level above, but that's a different issue...) I agree with Greg Woods - if a domain is authoritatively non-existent, I'd expect a sane mailer to bounce the message. Steinar Haug, Nethelp consulting, sthaug(a)nethelp.no

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Normal problems, only from small and medium ISPs
by Sean Donelan 03 Jan '00

03 Jan '00

Yesterday someone commented about the lack of "normal" problems you might expect on any day of the year. As far as I know, no large carrier, ISP or satellite company reported any problems Y2K or otherwise. Nevertheless small and medium ISPs continued to report the usual circuit problems and other issues right through the weekend. There did seem to be fewer trouble than average, but it wasn't zero. This was one of the issues I spoke about with the Feds earlier this summer, and one of the reasons why I pushed so hard to get reporting from small and medium ISPs. After all very few small and medium ISPs own their own facilities, so the circuit problems were likely in facilities owned by the larger carriers even though the carriers reported no problems. By listening to the small and medium providers, they would be more likely to hear about problems in the carrier facilities faster than the carriers would on their own. Last week one major carrier spokesperson was even quoted in an interview they were only going to report things required by the FCC, which as you know does not included any wireless or Internet problems.

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Re: mail does bounce (was: Customers down?)
by Sean Donelan 02 Jan '00

02 Jan '00

On Sun, 02 January 2000, Owen DeLong wrote: > I don't even assume that anyone elses mail system works, let > alone that it works this way, or even complies with the RFC's. > > There's way too much MicroSoft stuff out there to believe > any of that. I merely purport that the above is BCP. Could you point me to a written Best Common Practice which says this? Or is it simply one of those assumptions people like to make? The problem with assumptions is they work great, until someone makes a different one.

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Re: mail does bounce (was: Customers down?)
by owen＠dixon.delong.sj.ca.us 02 Jan '00

02 Jan '00

> On Sun, 02 January 2000, Owen DeLong wrote: > > I'll take a stab at this: > > > > Attempting to resolve a.b.c.d.e.f.g.h.i > > > > If you get back a return value from DNS that says > > "Authoritative answer, a.b.c.d.e.f.g.h.i does not exist" > > Bounce the mail. > > > > If you get back a return that says > > "Resolving a.b.c.d.e.f.g.h.i timed out without a return" > > Queue the mail. > > > > This also works for i, h.i, g.h.i, f.g.h.i, etc. > > I'm happy to agree this is a very sensible thing to do. However, > there is no requirement for any mailer to do it. Some mailers may, > but other mailers may not. So it is not very wise to assume all > mailers work the same as yours. > > There is a written recommendation that domains should have DNS > servers on seperate networks. There is no such recommendation > that mailers retry or queue mail when they can't reach DNS servers. > Sean, I don't even assume that anyone elses mail system works, let alone that it works this way, or even complies with the RFC's. There's way too much MicroSoft stuff out there to believe any of that. I merely purport that the above is BCP. Owen

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Re: mail does bounce (was: Customers down?)
by owen＠dixon.delong.sj.ca.us 02 Jan '00

02 Jan '00

> On Sun, Jan 02, 2000 at 12:31:00PM -0800, Owen DeLong wrote: > > Attempting to resolve a.b.c.d.e.f.g.h.i > > > > If you get back a return value from DNS that says > > "Authoritative answer, a.b.c.d.e.f.g.h.i does not exist" > > Bounce the mail. > > > > If you get back a return that says > > "Resolving a.b.c.d.e.f.g.h.i timed out without a return" > > Queue the mail. > > > > This also works for i, h.i, g.h.i, f.g.h.i, etc. > > I agree that this is the most sensible minimum functionality. What do you > break if you treat what you consider persistent terminal conditions as > transient? > Usually, if I send something to foo(a)delnog.org instead of foo(a)delong.org, I get a bounce back before I depart my MUA. You would break that. > Perhaps your business policy is to deliver all mail that can possibly be > delivered, making the assumption that everything's transient unless the system > has what it considers reasonable proof that it is indeed permanent (after > for instance several attempts spread out over a period of time). > I think that an authoritative nameserver saying "I know for certain that domain xyz doesn't exist." is reasonable proof that an error requiring intervention exists. > Personally, I don't like systems which do not have backup paths to deal with > transient conditions. And we do know that even "authoritative does not exist" > can be a transient error condition caused by a registry glitch etc. Sure, we > can all just ignore reality and assume we live in a perfect world, but.... > But a registry glitch is an error requiring intervention, therefore, I would much rather receive my mail back immediately so that I can intervene, than have it sit there while everything else breaks hoping that it will eventually clear itself. Owen > Cheers, > Chris > > -- > Christian Kuhtz Architecture, BellSouth.net > <ck(a)arch.bellsouth.net> -wk, <ck(a)gnu.org> -hm Atlanta, GA > "Speaking for myself only." >

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got any good dirt on 12.0.X(S)?
by scott w 02 Jan '00

02 Jan '00

I'm looking for anything on IOS 12.0.X(S). The Good, the Bad, *and* the Ugly. Mostly the Bad and Ugly.... I haven't found too much in the archives. If I missed it let me know, I've got my flameproof panties on... 8-) Most likely, private replies are best. I'll summarize later if there is sufficient interest. Thanks, scott

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BGP session resets
by Sean Donelan 02 Jan '00

02 Jan '00

In the last 48 hours I have received several reports about different providers resetting or reloading ALL of their external BGP sessions due to problems. I have not heard why the ISP reset their sessions, or details of what the problem is/was. At first I just assumed it was normal maintenance activity. ISPs do reload their BGP sessions on a regular basis. But as additional reports are coming in, it doesn't seem to be normal maintenance. The resets are ISP network-wide, and happening outside of typical maintenance windows. I have reports four different ISPs needed to reset their BGP. A small number, and it may just be because people are watching things a bit closer than normal. Does anyone know why ISPs are doing this?

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Re: mail does bounce (was: Customers down?)
by Sean Donelan 02 Jan '00

02 Jan '00

On Sun, 02 January 2000, Owen DeLong wrote: > I'll take a stab at this: > > Attempting to resolve a.b.c.d.e.f.g.h.i > > If you get back a return value from DNS that says > "Authoritative answer, a.b.c.d.e.f.g.h.i does not exist" > Bounce the mail. > > If you get back a return that says > "Resolving a.b.c.d.e.f.g.h.i timed out without a return" > Queue the mail. > > This also works for i, h.i, g.h.i, f.g.h.i, etc. I'm happy to agree this is a very sensible thing to do. However, there is no requirement for any mailer to do it. Some mailers may, but other mailers may not. So it is not very wise to assume all mailers work the same as yours. There is a written recommendation that domains should have DNS servers on seperate networks. There is no such recommendation that mailers retry or queue mail when they can't reach DNS servers.

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Re: mail does bounce (was: Customers down?)
by owen＠dixon.delong.sj.ca.us 02 Jan '00

02 Jan '00

> On Sat, 01 January 2000, "Steven J. Sobol" wrote: > > What I was referring to was a situation where the domain does exist in the > > root nameservers but the authoritative nameservers are unavailable. > > So .COM exists in the root servers? How do you decide to treat second > level domains (i.e. donelan.com) versus third level domains > (i.e. www.donelan.com) versus third level domains under country code > domains. > > > > > > I'll take a stab at this: Attempting to resolve a.b.c.d.e.f.g.h.i If you get back a return value from DNS that says "Authoritative answer, a.b.c.d.e.f.g.h.i does not exist" Bounce the mail. If you get back a return that says "Resolving a.b.c.d.e.f.g.h.i timed out without a return" Queue the mail. This also works for i, h.i, g.h.i, f.g.h.i, etc. Owen

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