Re: [gentoo-user] Re: Local mail server
* Grant Edwards: > Pricing is based on what people are willing to pay. People are willing > to pay extra for a static IPv6 address, therefore static IPv6 > addresses cost extra. Somewhere, and some people. I'd be interested to hear from users who still need to pay extra for IPv6. Here in Germany IPv6 usually comes at not extra cost (I write "usually" because I don't know every single ISP here; some only operate in a particular city.) -Ralph
Re: [gentoo-user] Local mail server
* antli...@youngman.org.uk: > An ISP will then be allocated the next 16 bits, giving them a 32-bit > address space to allocate to their customers - each ISP will have an > address space the size of IPv4?! ISPs can ask for several address spaces, each of which had a much, *much* larger address space than the whole of IPv4. My ISP (Deutsche Telekom) assigns /56 Subnets to Home Routers. Given that an IPv6 address encompasses 128 Bits, each household is thus provided with an address space of 2^(128-56) Bits. The whole of IPv4 spans only 2^32 Bits. Any halfway decent data center should, at least, hand out /64 Subnets for each and every hardware server and VM, free of charge. With virtu- alisation becoming mainstream, I'd prefer to have a /56 for the host server, so I can assign /64 subnets to each VM. A wider address space does not mean one makes use of every available address, of course. It just makes routing that much simpler, and there is no need for silly stuff like NAT. -Ralph
Re: [gentoo-user] OT: Can a linux vmware guest tell if its host is CPU constrained?
On Thu, Jul 30, 2020 at 2:52 AM Adam Carter wrote: >> >> > So should I run something like: date ; time > > 100%CPU for a minute> ; date ? >> >> No, date will pull from your RTC, which is usually kept up to date with an >> asynchronous >> counter. >> >> First check GNU top(1) and look in the %Cpu line for "st." That is % CPU >> time stolen. If it is >> nonzero then the guest time's accounting is probably working. It's not >> typical for the >> hypervisor to hide this information. It's really important for load >> balancing. > > > Thanks for that. I haven't seen any non-zero stolen time yet, however. > > FWIW vmstat also shows stolen time. Stolen time reporting through vmstat/top only works on xen and kvm hypervisors, it wasn't implemented for vmware. It actually looks like it was finally submitted for linux v5.7 (https://lore.kernel.org/lkml/20200331100353.ga37...@gmail.com/). If you want those numbers for older kernels, fetch this repository: https://github.com/dagwieers/vmguestlib and run vmguest-stats. You'll also need open-vm-tools installed. Have used this many times in the past and the numbers are good.
Re: [gentoo-user] Local mail server
On 30/07/2020 14:28, Remco Rijnders wrote: On Thu, Jul 30, 2020 at 01:48:05PM +0100, antlists wrote in : I don't think an ISP is supposed to allocate less ... I think your original message was open for multiple interpretations, or at least I read it as you saying there are 32 bit addresses the ISP allocates from. I now see the alternate one and the one you probably intended that there is 32 bits worth of /64's to hand out to customers. I'm sorry for misunderstanding at first. Yes, a mimimum of /64 is what is recommended (and needed to make stateless auto configuration work on the customers end). Whether the /64 you get allocated is dynamic or static, can still depend on the ISP's practises and business model. No problem. Many people aren't native English speakers (and I can get a little bit hot under the collar when Americans claim to speak English :-) so I have no problem with mis-understandings. Besides English I speak three other languages ranging from "get by" to "struggling", so I well understand all the problems caused by implicit nuances, differences in grammar, different mind-sets etc :-) Cheers, Wol
Re: [gentoo-user] Local mail server
On Thu, Jul 30, 2020 at 01:48:05PM +0100, antlists wrote in : I don't think an ISP is supposed to allocate less ... I think your original message was open for multiple interpretations, or at least I read it as you saying there are 32 bit addresses the ISP allocates from. I now see the alternate one and the one you probably intended that there is 32 bits worth of /64's to hand out to customers. I'm sorry for misunderstanding at first. Yes, a mimimum of /64 is what is recommended (and needed to make stateless auto configuration work on the customers end). Whether the /64 you get allocated is dynamic or static, can still depend on the ISP's practises and business model. Cheers, Remco
Re: [gentoo-user] Local mail server
On 30/07/2020 12:13, Remco Rijnders wrote: An IPv6 address is 128 bits in length. Usually an ISP allocates 64 bits to a single customer, allowing the systems on/behind that connection to automatically assign themselves an address based on their MAC address for example. Note that also allocations bigger than 64 bits are common so customers get 70 or 76 bits to use and can use multiple subnets on their home/business networks. I don't think an ISP is supposed to allocate less ... As I understood it, the first 64 bits are the "network address", ie sort-of assigned to the edge router, and the remaining 64 bits are assigned by the network operator. So in your scenario of customers getting more bits, they are effectively being assigned 2^6 or 2^12 network addresses. Exactly the scenario planned for high-level ISPs parcelling out address space to low-level ISPs. And looking at the wikipedia page, it looks like the ISP *must* allocate at least a /64, because the spec says each device allocates itself a least-significant-64 address at random using a collision-detect protocol. Which is why many simplistic algorithms include the MAC address to (try to) guarantee a unique address on the first attempt. Cheers, Wol
Re: [gentoo-user] Local mail server
Point is though, with IPv6 addresses are no longer a scarce commodity. The cost to an ISP to give you one IPv6 address (/128) is just the same as given you enough room for your own IPv4 internet (/64). Oops, brain freeze. A /64 gives you enough room for an IPv4 internet of IPv4 networks as IPv4 is just 32 bits.
Re: [gentoo-user] Local mail server
On Thu, Jul 30, 2020 at 10:05:46AM +0100, antlists wrote in : From what little I understand, IPv6 *enforces* CIDR. So, of the 64 network bits, maybe the first 16 bits are allocated to each high level allocator eg RIPE, ARIN etc. An ISP will then be allocated the next 16 bits, giving them a 32-bit address space to allocate to their customers - each ISP will have an address space the size of IPv4?! Each customer is then given one of these 64-bit address spaces for their local network. So routing tables suddenly become extremely simple - eactly the way IPv4 was intended to be. An IPv6 address is 128 bits in length. Usually an ISP allocates 64 bits to a single customer, allowing the systems on/behind that connection to automatically assign themselves an address based on their MAC address for example. Note that also allocations bigger than 64 bits are common so customers get 70 or 76 bits to use and can use multiple subnets on their home/business networks. Point is though, with IPv6 addresses are no longer a scarce commodity. The cost to an ISP to give you one IPv6 address (/128) is just the same as given you enough room for your own IPv4 internet (/64). Whether they make them static or dynamic depends on their policy and what their customers are willing to put up with / pay for.
Re: [gentoo-user] Local mail server
On 30/07/2020 00:23, james wrote: Very, Very interested in this thread. Another quesiton. If you have (2) blocks of IP6 address, can you use BGP4 (RFC 1771, 4271, 4632, 5678,5936 6198 etc ) and other RFC based standards to manage routing and such multipath needs? Who enforces what carriers do with networking. Here in the US, I'm pretty sure it's just up to the the Carrier/ISP/bypass_Carrier/backhaul-transport company) Conglomerates with IP resources, pretty much do what they want, and they are killing the standards based networking. If I'm incorrect, please educated me, as I have not kept up in this space, since selling my ISP more than (2) decades ago. The trump-china disputes are only accelerating open standards for communications systems, including all things TCP/IP. From what little I understand, IPv6 *enforces* CIDR. So, of the 64 network bits, maybe the first 16 bits are allocated to each high level allocator eg RIPE, ARIN etc. An ISP will then be allocated the next 16 bits, giving them a 32-bit address space to allocate to their customers - each ISP will have an address space the size of IPv4?! Each customer is then given one of these 64-bit address spaces for their local network. So routing tables suddenly become extremely simple - eactly the way IPv4 was intended to be. This may then mean that dynDNS is part of (needs to be) the IPv6 spec, because every time a client roams between networks, its IPv6 address HAS to change. I need to research more :-) Cheers, Wol
