default routes question or any way to do the rebundant

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1

Hi

ls it possible to have 2 default routes?
or how can I do the rebundant when the route is still
working either eth1 or eth2 down?

Router2
   192.168.0.2/20 eth1
   192.168.0.18/20 eth2
   10.0.0.1 eth3

ip route 0.0.0.0/0 192.168.0.1
ip route 0.0.0.0/0 192.168.0.17

or

ip route 0.0.0.0/0 192.168.0.1
ip route 0.0.0.0/0 192.168.0.17 2

Router1
  192.168.0.1 eth
  192.168.0.17 eth2
  172.16.0.1 eth3

host1 10.0.0.2 connects R2 couldn't ping host2
172.16.0.2 connects R1 when the link 192.168.0.1 is
down

host1-----R1--Switch---R2-----host2
            --Switch---

i am using freebsd router

Thank you for your help

2

NANOG is not a general purpose router help mailing list. Issues discussed here are supposed to be relevant to the North American ISP community.

Please take this question to a FreeBSD mailing list.

Thanks,
-Don

3

Donald Stahl wrote:

NANOG is not a general purpose router help mailing list. Issues
discussed here are supposed to be relevant to the North American ISP
community.

excuse? configuring routers is not operational in north america? have
you gone completely layer 2 over there?

randy

4

ls it possible to have 2 default routes?
  
No .. not in the literal sense.

or how can I do the rebundant when the route is still
working either eth1 or eth2 down?
  
What you do in this case is create an equal weighted preference for each of the two routes, along with tests to ensure each link is up and modify your pf rules accordingly.

example1 (this is for netfilter) : http://lartc.org/howto/lartc.rpdb.multiple-links.html
example2 (freebsd specific) : http://www.freebsddiary.org/phorum/read.php?f=6&i=79&t=79

As others have mentioned, this is a question for the various FreeBSD mailing lists ..

Cheers,

Michael Holstein
Cleveland State University

5

NANOG is not a general purpose router help mailing list. Issues
discussed here are supposed to be relevant to the North American ISP
community.

excuse? configuring routers is not operational in north america? have
you gone completely layer 2 over there?

Are you seriously going to sit there and claim that someone asking about how to set up 2 default routes on a FreeBSD box is operationally or technically relevant to the NANOG community at large?

I believe their email fails the NANOG pre-posting guide (specifically #3) and furthermore that it would be far better answered on a FreeBSD specific mailing list.

This same person posted a question on Wednesday about MTU's stating "Why? but I still don't know why mtu can cause this problem." I seriously doubt this was relevant to the thousands of people who read this list but I could be wrong about that one too.

Perhaps someone from the MLC can comment on whether these sorts of posts qualify as relevant.

On the other hand, if you really want to answer these sorts of questions then perhaps people can email you directly? I personally think NANOG has enough noise as it is.

-Don

6

annkok2001@yahoo.com (ann kok) writes:

Hi

ls it possible to have 2 default routes?
or how can I do the rebundant when the route is still
working either eth1 or eth2 down?
...
i am using freebsd router

see http://www.cctec.com/maillists/nanog/historical/9706/msg00237.html
and http://gatekeeper.hpl.hp.com/archive/pub/misc/vixie/ifdefault/

7

I've always been under the impression NANOG's primary goal is to
foster learning and best practices for operating networks. just
because a question is simplistic doesn't mean it isn't on topic and
helpful towards promoting best practices at large.

my two cents,
aaron

8

Sorry all. i don't want to make any argument

For me, i really want to get mailling list about
networking to help. and I heard there are professional
networking guys in nanog. they might help me.

I still have many networking questions.

for the mtu issue, I couldn't find out until I know
someone changes the mtu. it really made me panic
before.
honestly, telecom company couldn't help me. I still
don't know how they setup the jumbo frame in their
side but DSL clients are only using mtu1492.

Another question about private address, my router
upstream interface can listen many private address.
I asked the upstream ISP but they said they don't have
any private address export.
we have /30 connect to them. where is the private
addresses coming?
have you encountered this problem?

if you think my question is not good, please ignore it

Thank you again

9

Sorry all. i don't want to make any argument

Don't worry, the argument is elsewhere. :slight_smile:

For me, i really want to get mailling list about
networking to help. and I heard there are professional
networking guys in nanog. they might help me.

There's certainly a lot of clue here. Its just coloured by 15+ years
of jaded network and systems support. :slight_smile:

I still have many networking questions.

for the mtu issue, I couldn't find out until I know
someone changes the mtu. it really made me panic
before.
honestly, telecom company couldn't help me. I still
don't know how they setup the jumbo frame in their
side but DSL clients are only using mtu1492.

Approach it scientifically. The trouble with not having exposure to low-level
stuff as a pre-requisite for doing higher-level stuff is that you've probably
missed out on all of the boring details that you could feed into solving the
issue methodically. Path MTU discovery pops up as one of those things you'd
think about after you learn about ICMP and PMTU in an intro networking course
or book.

(Or in my case, junior sysadmin, IRC and hanging around NANOG/RIPE meetings..)

A lot of modern CPEs will actually rewrite the MSS of the TCP connection
to make sure frames aren't bigger than the ISP provided MTU, thus trying to
avoid PMTU. The trouble is that devices -other than the ISP/CPE- could be
filtering PMTU, and sometimes its unavoidable to run MTU < 1500 to the client.

(in fact, on a completely side note, sometimes you -want- to run small
client-facing MTUs.)

Another question about private address, my router
upstream interface can listen many private address.
I asked the upstream ISP but they said they don't have
any private address export.
we have /30 connect to them. where is the private
addresses coming?
have you encountered this problem?

Which private addresses? A number of ISPs will use RFC1918 addresses
on PtP links to clients (and their dial infrastructure!), assigning
real public IPs on the PPP end-points. Some others (like my 3G mobile
broadband provider) run their entire dial infrastructure and end-user
addressing on RFC1918 and do NAT elsewhere.

"Private address export" needs defining too?

Adrian

10

Is this for real?

Someone asks a harmless question about setting up multiple default
routes, not about Barack Obama or whether the moon is made of green
cheese, but about default routes.

Then 10 people decide to respond that this isn't appropriate for nanog.

Then 25 people decide to dispute that.

Then 50 people are arguing (ok maybe I exaggerate but just a little)
about it.

So the person who asked the original question feels bad and apologizes.

And 5 people decide to tell her there's nothing to apologize for.

And 10 people dispute that...and...what next? Oh, right, and next I
feel an urge to write this idiotic meta-meta-meta-note.

I think psychologists have a term for this, "chaotic instability
disorder" or something like that.

Maybe what we need are NANOG GREETERS!

Hello, welcome to Nanog, can we help you find something? Hello,
welcome to Nanog, can we help you find something?...

11

Blue light special in slot 5? V6 only STM64's now half price!

<personal opinion>

I dont think that there's any issue at all to be honest. NANOG isn't
just for the clued.

</personal opinion>

Best,

Marty

12

If we do not help the newbies how will they ever become clued. I can certainly remember when I did not know a bit from a byte.

Oh and btw I'll take 5 of those STM64's on special...

Regards all - Scott

Martin Hannigan wrote:

13

Scott McGrath wrote:

If we do not help the newbies how will they ever become clued. I can
certainly remember when I did not know a bit from a byte.

I agree, but I question if NANOG is the appropriate medium for such help. I
tend to (maybe mistakenly) assume a working knowledge of basic multihoming
concepts is essentially a prerequisite for active participation on the NANOG
mailing list. Isn't this akin to posting to a profesional mathematics forum
asking for help with your Algebra? I know I read the list for high-level
discussions of the issues facing North American network operators, not for a
rehash of multihoming 101. Certainly helping to educate newcomers can go a
long way towards making all of lives easier, but that seems outside the
scope of NANOG-L. If NANOG isn't the appropriate forum for those types of
discussions, what is? Where should we be referring people to have clue
bestowed upon them?

Is there a lack of alternatives out there for such discussion? [vendor]-nsp
seems like a decent choice for questions such as the one that sparked this
discussion. Inet-access used be a good place for finding that type of
information, but that list seems to be on life-support these days. Would it
be appropriate for NANOG to start such a list? (NANOG Lite?) Would anyone
bother subscribing/participating? Or are the available alternatives
sufficient?

Andrew Cruse

14

And more to the point - if somebody manages to go through all the hoops needed
to ask a basic question on the NANOG list, it demonstrates a desire to
accumulate clue - so we should encourage those people. I'll make the
prediction that in 5 years, the person who *started* this thread will be
substantially more clued than the lead network engineer at many AS's (you all
know the ones I mean - that AS that's 1 or 2 hops away from you that on a
weekly basis do something that makes you want to go and inject clue with a
baseball bat..)

15

Scott McGrath wrote:

If we do not help the newbies how will they ever become clued. I can certainly remember when I did not know a bit from a byte.

Oh and btw I'll take 5 of those STM64's on special...

I joined this group in hopes of getting clued through osmosis. The jury is still out on my success at that.

Don't need any STM64's, but if you've got any 7206s sitting around....

16

I'll take that bet Valdis

17

Whoops! I’m still coming to grips with multihoming. According to your thinking, my many years on the NANOG mailing list were wrong and you tell me I should leave.

I don’t think I can allow you to do that, Andrew.

Paul Vixie, Dillon, Bush, and others have given many examples of appropriate and concise direction giving to newby questioners. Follow their lead, please.

Cutler

18

In 1943 he (Einstein) answered a little girl who had difficulties in school
with mathematics.
"Do not worry about your difficulties in Mathematics. I can assure you mine are
still greater. Best regards Professor Albert Einstein."

http://www.einstein-website.de/z_kids/letterskids.html

19

That's cute Valdis, but did the little girl and Einstein force thousands of
people around the world to read their correspondence? I whole-heartily
encourage and thank anyone willing to take the time to help the original
poster. Off-list.

Andrew

20

Suggestion: Before creating list rule about appropriate level of
expertise in questions, wait until volume of question traffic merits
such. In my experience, easy questions sometimes even yield tips or
discussion useful to experts.

-- Ben