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There aren't enough private IPv4 addresses for large(ish) mobile networks to address all their customers devices. Some networks work around this by using public
by profmonocle 6y ago
There aren't enough private IPv4 addresses for large(ish) mobile networks to address all their customers devices. Some networks work around this by using public v4 addresses which simply aren't in use. The UK DOD's block has never been publicly advertised (AFAIK) so they decided it was a "safe" block to use for this purpose. This isn't a new practice - I remember seeing Sprint doing this same thing many years ago.
The "correct" way to handle this would be to reuse real private IPv4 addresses within your network by segmenting it somehow, or do what some networks have done (T-Mobile US is probably the biggest) - use IPv6 with NAT64. That lets them forego internal IPv4 entirely and only use it at the edge for NAT.
- rohan1024 6y agoSo if UK DOD chooses to publicly advertise someday my Internet will break. Good to know.
- api 6y agoNo, you just would not be able to reach UK DOD.
- rohan1024 6y agoOn reconnection got a 56.x ip so USPS as well.
- lmm 6y agoOr whoever they transfer their address space to, if they try to be more socially responsible, which might end up being the next cool startup.
- gruez 6y agoThat's the best case scenario, considering that most customers probably don't need to connect to UK DOD. With the way IPv4 shortages are going, the more likely scenario is that some cloud provider/cdn buys that range, and sites start breaking randomly for customers.
- Spooky23 6y agoPerhaps. They sold a block to Microsoft to host O365 and Azure AD components a few years ago!
- deleted 6y ago[deleted]
- deleted 6y ago[deleted]
- banana_giraffe 6y agoIs there a list or some way to discover which blocks are like this that aren't in use?
- p1mrx 6y agohttps://bgp.potaroo.net/ipv4-stats/prefixes_unadv_pool.txt https://bgp.potaroo.net/ipv4-stats/prefixes_unadv_pool.txt
- gpm 6y agoIs this complete? All of 4.0/8 10.0/8 12.0/8 15.0/8 16.0/8 17.0/8... are unrouted? Edit(v2): Complete list of unrouted (per that list) /8s along with their IANA designation 0: IANA - Local Identification 4, 15, 16, 32, 40, 44: Administered by ARIN 10: IANA - Private Use 12: AT&T Bell Laboratories 17: Apple Computer Inc. 38: PSINet, Inc 53: Daimler AG 55: DoD Network Information Center 57: Administered by RIPE NCC 73: ARIN 126: APNIC 127: IANA - Loopback 214: US-DOD 224 to 239: Multicast 240 to 255: Future use (designations from https://www.iana.org/assignments/ipv4-address-space/ipv4-address-space.xhtml https://www.iana.org/assignments/ipv4-address-space/ipv4-add...)
- quesera 6y ago> All of (...) 17.0/8... are unrouted? Definitely not complete: apple.com. 1424 IN A 17.172.224.47 apple.com. 1424 IN A 17.178.96.59 apple.com. 1424 IN A 17.142.160.59
- dylz 6y agoMost of these are routed and in very active use. I have suballocations of large chunks from 12/8 and 38/8. People will be unhappy if you picked most of them. 73/8 is entirely owned by Comcast and used for customers. 44 is no longer a /8, but sold+split and half in active use by AWS.
- tinus_hn 6y ago25.* is not larger than 10.*. What problem does this solve?