98 Matching Annotations
  1. Last 7 days
    1. v putt ( s )

      Maybe $$v_{putter}(s)$$ would have been more accurate

    2. we abbreviate the states high and low, and theactions search, wait, and recharge respectively by h , l , s , w , and re

      Abbreviation "re" is never used

    3. Puttingdoesn’t get us out of sand traps, so theyhave a value of 1

      Forgotten to reflect in Figure 3.3 (lower)

    4. Exercise 3.12 Give an equation for v ⇡ in terms of q ⇡ and ⇡. ⇤Exercise 3.13 Give an equation for q ⇡ in terms of v ⇡ and the four-argument p. ⇤

      Solution to this exercise can be later verified with definition (3.14)

  2. Mar 2024
    1. the following discussion

      if AdvValidTime > 2 || AdvValidTime > RemainingLifetime: set to AdvValidTime else if RemainingLifetime <= 2: ignore AdvValidTime else: set (decrease) to 2 the last 2 lines of which can be condensed to else: set to min(2, RemainingLifetime) Unit: hours

  3. Feb 2024
    1. The IEEE RAC is not aware of any cases, but if MAC-48 is used asthe name for any 48-bit MAC address, then EUI-48 is not the appropriatereplacement term for MAC-48, as EUI-48 only refers to individual,universally/globally unique network addresses.

      Read this text with emphasis on "any". I.e. the term "MAC-48" also includes locally administered MAC addresses (U/L bit set to 1), EUI-48 doesn't.

      Unfortunately, there doesn't seem to be a term like "MAC-64" to refer to same for a EUI-64.

    1. a personal firewall at the target host would not be able to mitigate this probing technique

      Couldn't the personal firewall just respond with the same ICMP messagt to unsolicited packets? Although it would still decrease the hop count by one. But the sender (the personal firewall) can just increase the hop limit by that number.

  4. Jan 2024
    1. rationale for looking treating the preference as a signed rather than unsigned value

      Maybe they wanted "00" to be the default. For no special reason...

    1. MAX_DESYNC_FACTOR

      Linux (according to sysctl doc) just uses 600 seconds (as absolute value, probably derived from 0.6 * TEMP_PREFERRED_LIFETIME) as default value for this. The RFC doesn't even allow changing it.

    2. lifetime of an address should be further reduced when privacy-meaningful events (such as a host attaching to a different network, or the regeneration of a new randomized Media Access Control (MAC) address) take place

      Isn't the address deleted in an event of a network disconnect anyway? Hmm, Linux has keep_addr_on_down sysctl option.

    3. REGEN_ADVANCE

      ``` 2s + (3x * (1x * 1s)) = 2s + 3s = 5 seconds

      values from the referenced documents: DupAddrDetectTransmits: default: 1x RetransTimer: default 1s Ethernet doesn't override any of these values ```

    4. 8981

      The following concepts are used before they're explained. - DESYNC_FACTOR - REGEN_ADVANCE

    5. It MUST be smaller than (TEMP_PREFERRED_LIFETIME - REGEN_ADVANCE).
    6. except for the transient period when a temporary address is being regenerated

      !

    1. at the expense of making the corresponding IPv6 addresses dependent on the underlying network interface card (i.e., the corresponding IPv6 addresses would typically change upon replacement of the underlying network interface card)

      If that's a problem, use DDNS.

    1. Note that the check against the prefix performed at the beginning of this step cannot always detect the address conflict in the list. It could be possible that an address already in the list, configured either manually or by DHCPv6, happens to be identical to the newly created address, whereas such a case should be atypical.

      So different prefix but resulted in same address

    2. race conditions when more than one node is trying to solicit for the same address at the same time

      i.e. both nodes failing DAD, so none of them using the tentative addr. (defined as DAD failure in section 5.4.3, last bullet)

  5. Dec 2023
    1. Temporary Stateless Addresses Auto-configuration

      Not more info than in the RFC

    1. becomes invalid in less than 1 second

      Explanation:

      TEMP_VALID_LIFETIME - TEMP_PREFERRED_LIFETIME < 1 second

      In this mentioned unfortunate case, the connection would be made less than 1 second before expiry.

      Full context: It would, upon expiry of the valid lifetime, just never enter a deprecated state, where it could keep existing connections open, but be immediately deleted.

    2. lifetime of temporary addresses must be statistically different for different addresses

      Implemented as DESYNC_FACTOR

    3. implementations MUST NOT employ the same secret_key for the generation of stable addresses [RFC7217] and the generation of temporary addresses via this algorithm

      So another secret to store

    4. and against those IIDs already employed in an address of the same network interface and the same network prefix

      don't forget

    5. limits the time window

      Although if you're continuously monitoring, chances are high you can even track IP address changes.

      Assuming that - there are only so many devices that at most one at a time is detected to have changed its IP address. - it's the same device, not a new one.

    1. (e.g., at random)

      e.g. IPv6 over PPP https://datatracker.ietf.org/doc/html/rfc5072#page-14

      methods for choosing the tentative interface identifier

      :

      If a good source of uniqueness cannot be found, it is recommended that a random number be generated.

    2. a client whose address cannot be mapped into a DNS name that also maps back into the same address

      called FCrDNS

    3. some servers

      e.g. mail servers

    4. an address does not reliably identify a particular device over time spans of more than a few minutes

      Or rather however long their dial-up line session is

    1. Figure 11 shows that the resolvers that account for 50% of theIPv6 ingress set have relatively close number of IPv4 and IPv6egress addresses; the left 50% resolvers have more IPv4 egress IPaddresses than IPv6 egress IP addresse

      Only Figure 12 shows that this is indeed the distribution (for 99%)

      Otherwise, I think that's only one possible distribution matching Figure 11. And still, like the author's mentioned analysis of Figure 9, under assumption of equal distribution.

    2. under the premise of resolverswith the same proportion

      "Under premise of equal distribution (of both groups: IPv4 and IPv6)" - Interesting wording and probably the only one you can make from an ECDF graph.

      Figure 10 actually conveniently shows that this conclusion (under the simplifying assumption) is false, as ~1% resolvers have >50% IPv6-to-IPv4 ratio (p99 = 0.5).

    3. Figure 9

      Description: The graph shows that resolvers overall have more IPv4 than IPv6 egress IP addresses. - ~99% of resolvers have about at most 10 IPv6 addresses only. - The top 20% of resolvers with most IPv4 egress addresses have >80 IPv4 egress addresses.

    4. Numbers

      "Amount" is more appropriate word

    5. 6

      So far, the paper has interesting references

    1. rule definitions for network packets that were found to be miscategorized by nDPI

      Spoiler: Was just Tor IP addresses on a shared cloud netblock (Akamai).

    2. Third and finally, for privacy and security reasons, these sites may need to be restricted or even blocked on some networks with high security requirements.

      The paragraph continues to elaborate on the impact of data breach of a consumer business website. However, blocking these websites from the company network wouldn't help prevent this data breach. -> Going offtopic

    3. In addition, there were different domain names and IP addresses obtained with the nslookup method, although they did not appear in the Wireshark results.

      Probably because of load balancing

    4. name of the organization

      That's WHOIS data (inetnum)

    5. it did not return IP addresses

      Because WHOIS was used when DNS should have been used.

  6. Nov 2023
    1. This suggests signal for malicious detection in activeDNS’s non-routable IPs.

      Really unclear to me why they went into detail on these malware domains. - It just seems a coincidence that these domains resolve to bogons. - Identifying active infections is impossible with active DNS.

    2. don

      Typo, should be "don't swap"

    3. The remainder of these domains provideinteresting cases for further study.

      Could these be domain transfers?

    1. Using this information, we were unable to uncover amuch larger set of malicious domains, allowing us to actively warnpotential targets.

      Attackers fault for token reuse

    1. for files that are gigabytes long

      This being a convenient special case where you know the expected amount of payload data ahead, but oftentimes you don't know (e.g. TCP connection reuse).

      But you could always redirect on start of the connection.

      (I didn't read further, though.)

    1. libprotoident [7], UPC [8], L7-filter [9], and TIE [18]limit their scope to protocol identification

      also references [8] and [9] are interchanged

    2. nDPI is prettyaccurate, even more accurate than PACE, the commercialversion of the old OpenDPI library on which nDPI is based

      ;D

    3. googlesyndacation

      Typo, meant syndication

    4. decoderfor SSL that extracts the host name of the contacted server

      read "decoder for TLS SNI"

    1. (1)

      They meant "(4)"

    2. lack of uptake of IPv6

      :(

    3. it is infeasible to exhaustively determine RTTs fromall Google PoPs to all authoritative name servers for domainsfor which our test server is also authoritative

      Because of amount of various zones, i.e.

      The SURFnet name server we used is authoritative for approximately 10,000 DNS zone

      Otherwise, for a single zone it's possible:

      e.g. gov.uk NS -> IP addresses (v4/v6) are only 3 ASs, one of which is AS1103/SurfNet itself. The others ones being (and their looking glass being): - AS786/Jisc (lg.ja.net) - AS702/Verizon (see PeeringDB for LG. Even though Verizon has multiple ASs, this particular AS is selectable as location from the LG)

      Re-check whenever Google changes its PoP prefixes.

    4. IP2Location dataset to map the ECS IPprefix to a country, as well as to coordinates

      Smells inaccurate, even at country level

    1. protocol

      transport layer protocol, not application layer protocol

    2. first 20 payload bytes in each direction

      For comparison: libprotoident does the first 4 bytes per direction

  7. Oct 2023
  8. Aug 2023
    1. 15 other internationalizedccTLDs run by India
    2. fixed this inconsistency on 2019-11-02 (we analyzed DNSOARC’s root zone file repository [4]).

      Can also be seen here visualized https://dns.coffee/zones/in

    3. either if thename server information retrieved and used in the following query is the oneprovided by the child, BIND caches the data from the paren

      (Grammar: Probably meant "even though" instead of "either if")

      I.e. if you query for "A" RR, BIND will - first query P(NS) (by the notation used in Table 4) (this query being as usual) - store this, P(NS), in cache - then query P(NS) for "NS" RR (query for C(NS)) - not store this, C(NS), in cache - then query on these NSs (C(NS)) for "A" RR (C(A)).

    4. it sends the parent an explicit NS query beforeperforming the A query. This is not a bad behavior, i.e., it does not violate RFCs,instead it tries to retrieve more authoritative information.

      They probably meant "it sends the child an explicit NS query".

      Seems so: - This word makes sense esp. in conj. with the provided reason "to retrieve more authoritative information". (Since there are only parent and child involved, the child being more authoritative since it is the actual nameserver in question) - And also: "the name server information retrieved and used in the following query is the one provided by the child" - whole logic of the remaining 8 line paragraph block

      It doesn't matter how the resolver asks the parent for the auth. nameservers. As long as they get them, that would not affect the result of this experiment. (How the resolver asks would be rather related to QNAME minimization.)

    5. he small number of child-centric resolversshown in §4 with Minimal Responses

      referring to §4.1 "Disjoint Parent and Child NSSet"

      Only about 40 vantage points receive data from the name servers in the child NSSet, indicating their resolvers likely performed explicit NS queries.

      And shortly before, the setup was explained:

      Only if resolvers perform explicit NS queries will they learn about [ns2,ns4].

      ([ns2,ns4] being said child NSSet)

    6. or because some probesshare upstream cache

      Not entirely sure what sharing upstream caches means. Just a shared cache (when resolver IPs belong to the same resolver service)? If so, the "or" is probably meant as "and possibly".

    7. unresponsive nameservers

      Server responds REFUSED status code (code 5) or does not respond at all if there is no DNS server anymore

    8. results in improper load balancing among the name servers

      I think this only applies to case (ii)

    9. Case (ii) may lead to unresponsive nameservers

      I think they meant case (iii)

    1. different responses from the Google Public DNS resolvers based on the domain

      It's just nlnetlabs.nl vs internet.nl, why does this cause a different behavior?

  9. Jul 2023
    1. Farsight - the Public Benefit Company that works to sustain the spirit of the Internet

      ...

  10. Jun 2023
    1. if the model refuses to stop on red light, how can we know if it successfullydetects the red light and the stop line

      They do have this feature vector output of the vision model (link), but still:

      This feature vector is uninterpretable to us

      In the end, for their problem, they used "KL-divergence loss" to filter out simulator artifacts (direction of image warp) from the feature vector, at train-time. This does not seem applicable for this case, though.

    2. suppose that the leading vehicle is moving slowly. For human drivers, we can choose toovertake it or not, which leads to at least two possible trajectories. Then, how can we decide whichtrajectory is better and force the model to learn it?

      "We use a type of MHP loss, to make sure the model can predict multiple possible trajectories." - https://blog.comma.ai/end-to-end-lateral-planning/ (cites [17])

      Doesn't this cover it?

    3. the WARP mechanismwill introduce image artifacts

      https://blog.comma.ai/end-to-end-lateral-planning/:

      For any large movements this seriously distorts the images

    4. 0.033 seconds

      1/30 of a second, i.e. 1 frame

    5. In this way, the model will not even have the chance to learn how to recover frommistakes. For example, if we manually feed a video sequence where the vehicle is going over thecenter line, which of course is a kind of dangerous driving, the model is likely to predict a trajectorythat keeps going straight, instead of returning to the correct line.

      Assumption or tested? Explained in comma.ai blog that is referenced in footnote (link):

      a model that just predicts a human’s most likely trajectory does not predict how to recover from mistakes

      They mean the model wouldn't even find back onto lane through the lane markings because it wasn't trained with such cases?

    6. Comma.ai’s blog

      Namely here: https://blog.comma.ai/end-to-end-lateral-planning/ ("we just apply a simple warp to the image")

    7. Openpilot loses the leading target when following a vehicleto turn, because the leading vehicle quickly vanishes

      😄

    8. Openpilot maynot handle it well and may alert the human driver to take control of the vehicle

      Afaik, it's not because openpilot misplanned something, it just expects the driver to help in applying steering force (torque), which because of car limitations it can't do by itself. Whether this is the case depends on your car.

    9. m/s

      Since when is meters per second a unit for distance? This should've been meters only.

    10. test

      train and test

    11. crowdsourcing

      Mapillary

    12. The two models are running simultaneously.

      Hence the name "dual-model deployment framework"

    13. We further compare the two model’s predicted trajectories in Figure 10b.

      Which is which? origin = Supercombo, extra = OP-Deepdive (i.e. the reconstructed one)

    14. daul

      typo, should be "dual" Occurs twice in document.

    15. Note that they arenot uniformly distributed between 0 and 10. Instead, they are dense in the near future and becomesparse as the time goes, which suggests that the model should focus more on the near future.

      They could have plotted that :) Plotted it myself then.

    1. The resulting feature vector only contains information relevant to the problem it is trained on, which is trajectory-planning on unwarped images.

      Causing it to have no sense for warping, therefore ignoring it.

    2. train the vision model with the simple approach described above

      How do you ensure that it actually strips out (does not forward) the information about the warp direction? How does such a training process look like?

      Ahh, see later:

      Unfortunately, our tests indicate this vector does still contain information about how the image is warped. To remove that information [...]

    3. it still doesn’t stay on track well

      Why is that? The trajectory seems right, so who's at fault? The car controller in determining the steering angle?

      Explained later:

      even in a simulation where we don’t introduce noise, there are linearization errors, model prediction errors, rounding errors, etc…

    4. MHP loss

      Isn't it called MTP?

    1. Thanks to the power of insourcing, we’ve been able to reduce manufacturing costs.

      A play on outsourcing.

    1. similar things are being worked on for longitudinal (gas/brake)
    1. stopping at traffic lights, going for green lights, stopping at stop signs