Re: [External] Re: uPRF strict more

2021-10-01 Thread Mark Tinka
On 10/1/21 19:28, Randy Bush wrote: in fact, this seems to be the modern conservative style for some years. i sometimes wonder if it is worth the config pain. If having routers dedicated to peering, transit or edge functions is worth the extra pain, in lieu of doing it all on one box?

Re: [External] Re: uPRF strict more

2021-10-01 Thread Mark Tinka
On 10/1/21 20:17, Adam Thompson wrote: Do people in other parts of the world have access (both physical and logical) to enough bilateral peering (and budgets...) that it makes sense to deploy a router per peer? Certainly not a router per peer, but a peering router per city, where it may

Re: [External] Re: uPRF strict more

2021-10-01 Thread Saku Ytti
──┘ > > > Adam Thompson > Consultant, Infrastructure Services > > 100 - 135 Innovation Drive > Winnipeg, MB, R3T 6A8 > (204) 977-6824 or 1-800-430-6404 (MB only) > athomp...@merlin.mb.ca > www.merlin.mb.ca > > From: NANOG on behalf of &g

Re: [External] Re: uPRF strict more

2021-10-01 Thread Adam Thompson
merlin.mb.ca/> From: NANOG on behalf of Randy Bush Sent: October 1, 2021 12:28 To: Mark Tinka Cc: North American Network Operators' Group Subject: Re: [External] Re: uPRF strict more > A partial table with no default is perfectly fine for a peering ro

Re: [External] Re: uPRF strict more

2021-10-01 Thread Randy Bush
> A partial table with no default is perfectly fine for a peering router. > > As long as your peering router knows how to get to your prefixes and > those of your customers, as well as the prefixes of the networks you > peer with, you're good to go. in fact, this seems to be the modern

Re: uPRF strict more

2021-10-01 Thread Adam Thompson
Android<https://aka.ms/AAb9ysg> From: Brian Johnson Sent: Friday, October 1, 2021 8:31:15 AM To: Adam Thompson Cc: Amir Herzberg ; Randy Bush ; North American Network Operators' Group Subject: Re: uPRF strict more For strict-mode... Completely

Re: uPRF strict more

2021-10-01 Thread Brian Johnson
Winnipeg, MB, R3T 6A8 > (204) 977-6824 or 1-800-430-6404 (MB only) > athomp...@merlin.mb.ca <mailto:athomp...@merlin.mb.ca> > www.merlin.mb.ca <http://www.merlin.mb.ca/> > From: NANOG on behalf of > Amir Herzberg > Sent: September 28, 2021 20:06 > To: Randy Bush

Re: [External] Re: uPRF strict more

2021-09-30 Thread Mark Tinka
On 10/1/21 01:51, Valdis Klētnieks wrote: Am I insufficently caffienated, or is uRPF the least of your problems if you don't have a full table *and* don't have a default route? A partial table with no default is perfectly fine for a peering router. As long as your peering router knows how

Re: [External] Re: uPRF strict more

2021-09-30 Thread Valdis Klētnieks
On Thu, 30 Sep 2021 18:12:51 +0200, Mark Tinka said: > I should have said "If you don't plan to run a full BGP table on a > device without a default a route as well, Am I insufficently caffienated, or is uRPF the least of your problems if you don't have a full table *and* don't have a default

Re: [External] Re: uPRF strict more

2021-09-30 Thread Sabri Berisha
- On Sep 30, 2021, at 9:13 AM, Andrew Smith andrew.william.sm...@gmail.com wrote: Hi, > In Ciscoland, you do have to explicitly state that the default route is > eligible > for URPF verification, otherwise you'll get unexpected traffic drops. > ip verify unicast source reachable-via any

RE: [External] Re: uPRF strict more

2021-09-30 Thread Brian Turnbow via NANOG
Hi > > > What it does allow is for *deliberate* blackholing for traffic; if you > > null-route a prefix, you now block incoming traffic from that subnet > > as well. This can be useful and it is how we are using URPF. > > I don't think it is implied here, but just for clarification this is >

Re: [External] Re: uPRF strict more

2021-09-30 Thread Saku Ytti
On Thu, 30 Sept 2021 at 19:00, Hunter Fuller via NANOG wrote: > What it does allow is for *deliberate* blackholing for traffic; if you > null-route a prefix, you now block incoming traffic from that subnet > as well. This can be useful and it is how we are using URPF. I don't think it is

Re: [External] Re: uPRF strict more

2021-09-30 Thread Andrew Smith
In Ciscoland, you do have to explicitly state that the default route is eligible for URPF verification, otherwise you'll get unexpected traffic drops. ip verify unicast source reachable-via any allow-default And yes, it's main purpose is for implementing source-based remotely-triggered

Re: [External] Re: uPRF strict more

2021-09-30 Thread Mark Tinka
On 9/30/21 17:56, Hunter Fuller wrote: On Thu, Sep 30, 2021 at 12:08 AM Mark Tinka wrote: If you don't plan to run a full BGP table on a device, don't enable uRPF, even loose-mode. At least in Ciscoland, loose URPF checks will pass if you have a default route. So I do not think it could

Re: [External] Re: uPRF strict more

2021-09-30 Thread Hunter Fuller via NANOG
On Thu, Sep 30, 2021 at 12:08 AM Mark Tinka wrote: > If you don't plan to run a full BGP table on a device, don't enable uRPF, > even loose-mode. At least in Ciscoland, loose URPF checks will pass if you have a default route. So I do not think it could result in inadvertent blackholing of

Re: uPRF strict more

2021-09-30 Thread Blake Hudson
On 9/29/2021 5:30 PM, Sabri Berisha wrote: - On Sep 29, 2021, at 8:03 AM, Blake Hudson bl...@ispn.net wrote: Hi Blake,     200 deny ip 10.0.0.0 0.255.255.255 any (91057035 matches)     210 deny ip 172.16.0.0 0.15.255.255 any (1366408 matches)     220 deny ip 192.168.0.0 0.0.255.255

Re: uPRF strict more

2021-09-29 Thread Mark Tinka
On 9/29/21 20:14, Phil Bedard wrote: Disclosure I work for Cisco and try to look after some of their peering guidelines. Agree with Adam’s statement, use uRPF on edge DIA customers.  Using it elsewhere on the network eventually is going to cause some issue and its usefulness today is

Re: uPRF strict more

2021-09-29 Thread Mark Tinka
On 9/29/21 19:07, Adam Thompson wrote: We just ran into a typical case where uRPF caused a partial outage for one of my customers: the customer is multi-homed, with another provider that I'm *also*​ connected to.  Customer advertised a longer-prefix to the other guy, so I started sending

Re: uPRF strict more

2021-09-29 Thread Mark Tinka
On 9/29/21 23:36, Anoop Ghanwani wrote: This is not true for all ASICs.  Some ASICs choose to incur the penalty in a different way, e.g., by halving the prefix tables.  The prefix table is then duplicated so that uRPF SA and forwarding DA lookups can happen in parallel.  What kind of

Re: uPRF strict more

2021-09-29 Thread Sabri Berisha
- On Sep 29, 2021, at 8:03 AM, Blake Hudson bl...@ispn.net wrote: Hi Blake, >     200 deny ip 10.0.0.0 0.255.255.255 any (91057035 matches) >     210 deny ip 172.16.0.0 0.15.255.255 any (1366408 matches) >     220 deny ip 192.168.0.0 0.0.255.255 any (18325538 matches) These could perhaps be

Re: uPRF strict more

2021-09-29 Thread brad dreisbach
On Wed, Sep 29, 2021 at 11:38:19PM +0200, Baldur Norddahl wrote: On Wed, 29 Sept 2021 at 22:07, Jean St-Laurent via NANOG wrote: Thanks a lot for sharing. So 100 Gbps at line rate with 80B frames is about ~150 Mpps. 100 Gbps at line rate with 208B frames is about ~60 Mpps. It's a

Re: uPRF strict more

2021-09-29 Thread Baldur Norddahl
On Wed, 29 Sept 2021 at 22:07, Jean St-Laurent via NANOG wrote: > Thanks a lot for sharing. > > So 100 Gbps at line rate with 80B frames is about ~150 Mpps. > > 100 Gbps at line rate with 208B frames is about ~60 Mpps. > > It's a significant penalty. > Full rate small packets would be an attack

Re: uPRF strict more

2021-09-29 Thread Anoop Ghanwani
> Jean > > -Original Message- > From: brad dreisbach > Sent: September 29, 2021 3:33 PM > To: Jean St-Laurent > Cc: 'brad dreisbach' ; 'Phil Bedard' < > bedard.p...@gmail.com>; 'North American Network Operators' Group' < > nanog@nanog.org> > Subject:

RE: uPRF strict more

2021-09-29 Thread Jean St-Laurent via NANOG
American Network Operators' Group' Subject: Re: uPRF strict more On Wed, Sep 29, 2021 at 04:07:19PM -0400, Jean St-Laurent wrote: >Thanks a lot for sharing. > >So 100 Gbps at line rate with 80B frames is about ~150 Mpps. > >100 Gbps at line rate with 208B frames is about ~6

RE: uPRF strict more

2021-09-29 Thread Jean St-Laurent via NANOG
dreisbach' ; 'Phil Bedard' ; 'North American Network Operators' Group' Subject: Re: uPRF strict more On Wed, Sep 29, 2021 at 02:54:43PM -0400, Jean St-Laurent wrote: >Hi Brad, > >I'd be interested to hear more about this pps penalty. Do we talk about 5% >penalty or something closer to

Re: uPRF strict more

2021-09-29 Thread brad dreisbach
Sent: September 29, 2021 2:35 PM To: Phil Bedard Cc: North American Network Operators' Group Subject: Re: uPRF strict more On Wed, Sep 29, 2021 at 06:14:21PM +, Phil Bedard wrote: Disclosure I work for Cisco and try to look after some of their peering guidelines. Agree with Adam’s statement

RE: uPRF strict more

2021-09-29 Thread Jean St-Laurent via NANOG
Sent: September 29, 2021 2:35 PM To: Phil Bedard Cc: North American Network Operators' Group Subject: Re: uPRF strict more On Wed, Sep 29, 2021 at 06:14:21PM +, Phil Bedard wrote: >Disclosure I work for Cisco and try to look after some of their peering >guidelines. > >Agree

Re: uPRF strict more

2021-09-29 Thread brad dreisbach
American Network Operators' Group Subject: Re: uPRF strict more We just ran into a typical case where uRPF caused a partial outage for one of my customers: the customer is multi-homed, with another provider that I'm also​ connected to. Customer advertised a longer-prefix to the other guy, so I

Re: uPRF strict more

2021-09-29 Thread Phil Bedard
, Randy Bush Cc: North American Network Operators' Group Subject: Re: uPRF strict more We just ran into a typical case where uRPF caused a partial outage for one of my customers: the customer is multi-homed, with another provider that I'm also​ connected to. Customer advertised a longer-prefix

Re: uPRF strict more

2021-09-29 Thread Adam Thompson
...@merlin.mb.ca<mailto:athomp...@merlin.mb.ca> www.merlin.mb.ca<http://www.merlin.mb.ca/> From: NANOG on behalf of Amir Herzberg Sent: September 28, 2021 20:06 To: Randy Bush Cc: North American Network Operators' Group Subject: Re: uPRF strict more Randy, gr

Re: uPRF strict more

2021-09-29 Thread Blake Hudson
On 9/29/2021 9:27 AM, Mark Tinka wrote: On 9/29/21 16:21, Blake Hudson wrote: I do not use uRPF on upstream/transit/IX links or with multi-homed customers - or anywhere else where traffic could be asymmetrical; I prefer to use stateless ACLs at these locations. On peering and transit

Re: uPRF strict more

2021-09-29 Thread Mark Tinka
On 9/29/21 16:21, Blake Hudson wrote: I do not use uRPF on upstream/transit/IX links or with multi-homed customers - or anywhere else where traffic could be asymmetrical; I prefer to use stateless ACLs at these locations. On peering and transit routers, on ports facing the remote side, we

Re: uPRF strict more

2021-09-29 Thread Blake Hudson
As an eyeball network operator (Cable, DSL, Fiber) we use uRPF strict mode on customer facing ports on the BRAS gear. Our access gear also tends to include source address verification via DHCP snooping (as well as limits on the number of DHCP leases and/or MAC addresses each customer is

Re: uPRF strict more

2021-09-29 Thread John Kristoff
On Tue, 28 Sep 2021 17:47:41 -0700 Randy Bush wrote: > do folk use uPRF strict mode? Presumably you mean uRPF. As of a few months ago, the .edu I was doing netops at, Juniper's 'rpf-check' option was set on all the edge interfaces where there were only end hosts. This is strict mode. The

Re: uPRF strict more

2021-09-29 Thread Barry Greene
uRPF Strict mode was always suppose a widget for source address validation (SAV). Just like DHCP Lease Query (DOCSIS), the TR-69 ACLs, general ACLs, and other vendor specific widgets. Like all widgets, there are places where it works and other place were it does not. The key principle is to

Re: uPRF strict more

2021-09-29 Thread Mark Tinka
On 9/29/21 11:12, Nick Hilliard wrote: urpf has its place if your network config build processes aren't automated to the point that it's no longer necessary.  It would be a net security loss to the internet not to have it widely implemented on access devices. As little as 12 months

Re: uPRF strict more

2021-09-29 Thread Mark Tinka
On 9/29/21 08:03, Saku Ytti wrote: Vast majority of access ports are stubby, with no multihoming or redundancy. And uRPF strict is indeed used often here, but answer very rarely if ever applies for non-stubby port. Having said that, I'm not convinced anyone should use uRPF at all. Because

Re: uPRF strict more

2021-09-29 Thread Mark Tinka
On 9/29/21 02:47, Randy Bush wrote: do folk use uPRF strict mode? i always worried about the multi-homed customer sending packets out the other way which loop back to me; see RFC 8704 §2.2 We do loose-mode for BGP customers, regardless of whether they are single- or multi-homed. We do

RE: uPRF strict more

2021-09-29 Thread Brian Turnbow via NANOG
Hi, > Having said that, I'm not convinced anyone should use uRPF at all. > Because you should already know what IP addresses are possible behind the > port, if you do, you can do ACL, and ACL is significantly lower cost in PPS > in a > typical modern lookup engine. > uRPF still has it's place

Re: uPRF strict more

2021-09-29 Thread Nick Hilliard
Saku Ytti wrote on 29/09/2021 07:03: Having said that, I'm not convinced anyone should use uRPF at all. Because you should already know what IP addresses are possible behind the port, if you do, you can do ACL, and ACL is significantly lower cost in PPS in a typical modern lookup engine. urpf

Re: uPRF strict more

2021-09-29 Thread Saku Ytti
Vast majority of access ports are stubby, with no multihoming or redundancy. And uRPF strict is indeed used often here, but answer very rarely if ever applies for non-stubby port. Having said that, I'm not convinced anyone should use uRPF at all. Because you should already know what IP addresses

Re: uPRF strict more

2021-09-28 Thread Amir Herzberg
Randy, great question. I'm teaching that it's very rarely, if ever, used (due to high potential for benign loss); it's always great to be either confirmed or corrected... So if anyone replies just to Randy - pls cc me too (or, Randy, if you could sum up and send to list or me - thanks!) Amir --