nanog mailing list archives
Re: Anycast but for egress
From: Christopher Morrow <morrowc.lists () gmail com>
Date: Fri, 30 Jul 2021 12:49:45 -0400
On Thu, Jul 29, 2021 at 4:58 PM Joe Maimon <jmaimon () jmaimon com> wrote:
Vimal wrote:(Unsure if this is the right forum to ask this question, but here goes:) From what I understand, IP Anycast can be used to steer traffic into a server that's close to the client. I am curious if anyone here has/encountered a setup where they use anycast IP on their gateways... to have a predictable egress IP for their traffic, regardless of where they are located? For example, a search engine crawler could in principle have the same IP advertised all over the world, but it looks like they don't... I wonder why? -- VimalIts definitely possible, but would need a layer of software (kernel mode) on all the anycast holders synchronizing state to ensure asymmetric replies/connections get forwarded/shifted to the correct host.
is it actually that hard? isn't it more like: "use an outbound path local to that inbound path cone which NAT's (or proxy's or...) to a small set of staticlly assigned addresses" Provided you don't re-use the outbound addresses on different deployments this should 'just work'[tm] 'anycast but outbound' is really: "get me local nat pools for my service by locality" I think this is, bascially, what every enterprise network in the world does, effectively. If the goals are worth that kind of effort is another question. And
performance is likely to be "tricky".
Current thread:
- Re: Anycast but for egress, (continued)
- Re: Anycast but for egress Baldur Norddahl (Jul 28)
- Re: Anycast but for egress Mark Tinka (Jul 28)
- Re: Anycast but for egress Randy Bush (Jul 28)
- Re: Anycast but for egress Bill Woodcock (Jul 28)
- Re: Anycast but for egress Mark Tinka (Jul 28)
- Re: Anycast but for egress Vimal (Jul 28)
- Re: Anycast but for egress William Herrin (Jul 28)
- Re: Anycast but for egress Glenn McGurrin via NANOG (Jul 28)
- Re: Anycast but for egress Vimal (Jul 29)
- Re: Anycast but for egress Christopher Morrow (Jul 30)