[opensource-dev] Network characteristics (was: Concerned about frequent crashes

[Lee ponzu]

I am not expecting LL to support my pitiful Satellite connection.  Besides,
I am moving to Seattle, and will soon have a *real* network connection.

Nonetheless, I thought I would report my Netalyzer analysis here.  As you
can seen, slow DNS and slow TCP setup are two of its characteristics.  Maybe
a LL network engineer reading through this would see some simple solution to
some problems, such as making timeouts a little higher or some such.

The ICSI Netalyzr <http://netalyzr.icsi.berkeley.edu/index.html>
Start » Analysis » Results
Result Summary
+/– (help <http://n4.netalyzr.icsi.berkeley.edu/help.html>)
75-105-19-116.cust.wildblue.net / 75.105.19.116
Recorded at 14:14 EDT (18:14 UTC), Aug 07 2011.
Permalink<http://netalyzr.icsi.berkeley.edu/restore/id=321194b2-30780-3d0a3e7b-7082-4da9-bce0>
. Client<http://n4.netalyzr.icsi.berkeley.edu/transcript/id=321194b2-30780-3d0a3e7b-7082-4da9-bce0/side=client>
/server<http://n4.netalyzr.icsi.berkeley.edu/transcript/id=321194b2-30780-3d0a3e7b-7082-4da9-bce0/side=server>
 transcript.
------------------------------
Summary of Noteworthy Events –
Major Abnormalities

   - Your ISP's DNS server is slow to lookup names
<http://n4.netalyzr.icsi.berkeley.edu/summary/id=321194b2-30780-3d0a3e7b-7082-4da9-bce0#dns_properties>

Minor Aberrations

   - The measured network latency and packet loss were somewhat high
<http://n4.netalyzr.icsi.berkeley.edu/summary/id=321194b2-30780-3d0a3e7b-7082-4da9-bce0#latency>
   - The measured time to set up a TCP connection was somewhat high
<http://n4.netalyzr.icsi.berkeley.edu/summary/id=321194b2-30780-3d0a3e7b-7082-4da9-bce0#tcplatency>
   - The network measured bursts of packet loss
<http://n4.netalyzr.icsi.berkeley.edu/summary/id=321194b2-30780-3d0a3e7b-7082-4da9-bce0#burstloss>
   - Network bandwidth may be low
<http://n4.netalyzr.icsi.berkeley.edu/summary/id=321194b2-30780-3d0a3e7b-7082-4da9-bce0#BandwidthResult>
   - Network packet buffering may be excessive
<http://n4.netalyzr.icsi.berkeley.edu/summary/id=321194b2-30780-3d0a3e7b-7082-4da9-bce0#BufferResult>
   - We detected an HTTP proxy due to added or changed HTTP traffic
<http://n4.netalyzr.icsi.berkeley.edu/summary/id=321194b2-30780-3d0a3e7b-7082-4da9-bce0#HeaderProxy>
   - Not all DNS types were correctly processed
<http://n4.netalyzr.icsi.berkeley.edu/summary/id=321194b2-30780-3d0a3e7b-7082-4da9-bce0#resolverProbing>

Address-based Tests +
NAT detection (? <http://n4.netalyzr.icsi.berkeley.edu/info_nat_detect.html>):
NAT Detected
Local Network Interfaces
(?<http://n4.netalyzr.icsi.berkeley.edu/info_local_interface.html>):
OK
DNS-based host information
(?<http://n4.netalyzr.icsi.berkeley.edu/info_dns_hostinfo.html>):
OK
NAT support for Universal Plug and Play (UPnP)
(?<http://n4.netalyzr.icsi.berkeley.edu/info_upnp.html>):
Yes
Reachability Tests +
TCP connectivity
(?<http://n4.netalyzr.icsi.berkeley.edu/info_tcp_connectivity.html>):
OK
UDP connectivity
(?<http://n4.netalyzr.icsi.berkeley.edu/info_udp_connectivity.html>):
OK
Traceroute (? <http://n4.netalyzr.icsi.berkeley.edu/info_traceroute.html>):
OK
Path MTU (? <http://n4.netalyzr.icsi.berkeley.edu/info_mtu.html>): OK
Network Access Link Properties –
Network latency measurements
(?<http://n4.netalyzr.icsi.berkeley.edu/info_latency.html>):
Latency: 1900ms Loss: 3.5%
The round-trip time (RTT) between your computer and our server is 1900 msec,
which is quite high. This may be due to a variety of factors, including a
significant distance between your computer and our server, a particularly
slow or poor network link, or problems in your network.
We recorded a packet loss of 3.5%. This loss rate can result in noticeable
performance problems. It could be due either to significant load on our
servers due to a large number of visitors, or problems with your network.
All the packet loss appears to have occurred on the path from our server to
your computer.
TCP connection setup latency
(?<http://n4.netalyzr.icsi.berkeley.edu/info_tcp_latency.html>):
2700ms
The time it takes for your computer to set up a TCP connection with our
server is 2700 msec, which is quite high. This may be due to a variety of
factors, including a significant distance between your computer and our
server, a particularly slow or poor network link, or problems in your
network.
Network background health measurement
(?<http://n4.netalyzr.icsi.berkeley.edu/info_burst_loss.html>):
3 transient outages, longest: 0.8 seconds
During most of Netalyzr's execution, the applet continuously measures the
state of the network in the background, looking for short outages. During
testing, the applet observed 3 such outages. The longest outage lasted for
0.8 seconds. This suggests a general problem with the network where
connectivity is intermittent. This loss might also cause some of Netalyzr's
other tests to produce incorrect results.
Network bandwidth measurements
(?<http://n4.netalyzr.icsi.berkeley.edu/info_bandwidth.html>):
Upload 53 Kbit/sec, Download 240 Kbit/sec
Your Uplink: We measured your uplink's sending bandwidth at 53 Kbit/sec.
This rate could be considered somewhat slow, and may affect your user
experience if you perform large transfers.
Your Downlink: We measured your downlink's receiving bandwidth at 240
Kbit/sec. This rate could be considered quite slow, and will affect your
user experience if you perform large transfers.
Network buffer measurements
(?<http://n4.netalyzr.icsi.berkeley.edu/info_buffer.html>):
Uplink 6000 ms, Downlink 2500 ms
We estimate your uplink as having 6000 msec of buffering. This is quite
high, and you may experience substantial disruption to your network
performance when performing interactive tasks such as web-surfing while
simultaneously conducting large uploads. With such a buffer, real-time
applications such as games or audio chat can work quite poorly when
conducting large uploads at the same time.
We estimate your downlink as having 2500 msec of buffering. This is quite
high, and you may experience substantial disruption to your network
performance when performing interactive tasks such as web-surfing while
simultaneously conducting large downloads. With such a buffer, real-time
applications such as games or audio chat can work quite poorly when
conducting large downloads at the same time.
HTTP Tests –
Address-based HTTP proxy detection
(?<http://n4.netalyzr.icsi.berkeley.edu/info_httpproxy_addr.html>):
OK
We detected no explicit sign of HTTP proxy via IP address changes.
Content-based HTTP proxy detection
(?<http://n4.netalyzr.icsi.berkeley.edu/info_httpproxy_header.html>):
Warning

Changes to headers or contents sent between the applet and our HTTP server
show the presence of an otherwise unadvertised HTTP proxy.

The detected HTTP proxy changed either the headers the applet sent or the
HTTP response from the server. We have captured the changes for further
analysis.
HTTP proxy detection via malformed requests
(?<http://n4.netalyzr.icsi.berkeley.edu/info_httpproxy_malformed.html>):
OK
Deliberately malformed HTTP requests arrive at our server unchanged. Thus,
the proxies along your path are able to transparently forward invalid HTTP
traffic.
Filetype-based filtering
(?<http://n4.netalyzr.icsi.berkeley.edu/info_content_filters.html>):
OK
We did not detect file-content filtering.
HTTP caching behavior
(?<http://n4.netalyzr.icsi.berkeley.edu/info_httpcache.html>):
OK
We detected no signs of a transparent HTTP cache in your network path.
JavaScript-based tests
(?<http://n4.netalyzr.icsi.berkeley.edu/info_javascript.html>):
OK
The applet did not execute within a frame.
Your web browser reports the following cookies for our web page:

   - netAlizEd = BaR (set by our server)
   - netalyzrStatus = running (set by our server)

Your web browser was unable to fetch an image using IPv6.
DNS Tests –
Restricted domain DNS lookup
(?<http://n4.netalyzr.icsi.berkeley.edu/info_dns_restricted.html>):
OK
We can successfully look up a name which resolves to the same IP address as
our webserver. This means we are able to conduct many of the tests on your
DNS server.
Unrestricted domain DNS lookup
(?<http://n4.netalyzr.icsi.berkeley.edu/info_dns_unrestricted.html>):
OK
We can successfully look up arbitrary names from within the Java applet.
This means we are able to conduct all test on your DNS server.
Direct DNS support
(?<http://n4.netalyzr.icsi.berkeley.edu/info_direct_dns.html>):
OK
All tested DNS types were received OK.
Direct EDNS support
(?<http://n4.netalyzr.icsi.berkeley.edu/info_edns_connectivity.html>):
OK
EDNS-enabled requests for small responses are answered successfully.
EDNS-enabled requests for medium-sized responses are answered successfully.
EDNS-enabled requests for large responses are answered successfully.
DNS resolver address
(?<http://n4.netalyzr.icsi.berkeley.edu/info_dns_resolver.html>):
OK
The IP address of your ISP's DNS Resolver is 75.104.128.41, which does not
resolve. Additional nameservers observed for your host: 75.104.128.40.
DNS resolver properties
(?<http://n4.netalyzr.icsi.berkeley.edu/info_dns_resolver_behavior.html>):
Lookup latency 1900ms
Your ISP's DNS resolver requires 1900 msec to conduct an external lookup. It
takes 84 msec for your ISP's DNS resolver to lookup a name on our server.
This is particularly slow, and you may see significant performance
degradation as a result.
Your resolver correctly uses TCP requests when necessary.
Your resolver is using QTYPE=A for default queries.
Your host or resolver also performs IPv6 queries in addition to IPv4
queries.
Your DNS resolver requests DNSSEC records.
Your DNS resolver advertises the ability to accept DNS packets of up to 4096
bytes.
Your DNS resolver can successfully receive a smaller (~1400 byte) DNS
response.
Your DNS resolver can successfully receive a large (>1500 byte) DNS
response.
Your DNS resolver can successfully accept large responses.
Your resolver does not use 0x20 randomization, but will pass names in a
case-sensitive manner.
Your NAT has a built-in DNS proxy.
Your ISP's DNS server cannot use IPv6.
No transport problems were discovered which could affect the deployment of
DNSSEC.
Direct probing of DNS resolvers
(?<http://n4.netalyzr.icsi.berkeley.edu/info_dns_resolver_probes.html>
)
Your system is configured to use 1 DNS resolver(s).
The resolver at 192.168.11.1 was unable to process the following tested
types:

   - Medium (~1300B) TXT records
   - Large (~3000B) TXT records

It does not validate DNSSEC. It does not wildcard NXDOMAIN errors. The
resolver reports the following properties:

   - Hostname: l25r1105m40
   - Version: dnsmasq-2.55
   - Authors: Simon Kelley
   - Copyright: Copyright (c) 2000-2010 Simon Kelley

DNS glue policy (? <http://n4.netalyzr.icsi.berkeley.edu/info_dns_glue.html>):
OK
Your ISP's DNS resolver does not accept generic additional (glue) records —
good.
Your ISP's DNS resolver does not accept additional (glue) records which
correspond to nameservers.
Your ISP's DNS resolver does not follow CNAMEs.
DNS resolver port randomization
(?<http://n4.netalyzr.icsi.berkeley.edu/info_dns_random.html>):
OK
Your ISP's DNS resolver properly randomizes its local port number.

The following graph shows DNS requests on the x-axis and the detected source
ports on the y-axis.

[image: port sequence plot]
DNS lookups of popular domains
(?<http://n4.netalyzr.icsi.berkeley.edu/info_dnslookups.html>):
OK
79 of 79 popular names were resolved successfully. Show all names.
13 popular names have a mild anomaly. The ownership suggested by the reverse
name lookup does not match our understanding of the original name. The most
likely cause is the site's use of a Content Delivery Network. Show all names
.
2 popular names have a mild anomaly: we are unable to find a reverse name
associated with the IP address provided by your ISP's DNS server. This is
most likely due to a slow responding DNS server or misconfiguration on the
part of the domain owner. Show all names.
DNS external proxy
(?<http://n4.netalyzr.icsi.berkeley.edu/info_dns_proxy.html>):
OK
Your host ignores external DNS requests.
DNS results wildcarding
(?<http://n4.netalyzr.icsi.berkeley.edu/info_dns_wildcarding.html>):
OK
Your ISP correctly leaves non-resolving names untouched.
DNS-level redirection of specific sites
(?<http://n4.netalyzr.icsi.berkeley.edu/info_dns_mitm.html>):
OK
Your ISP does not appear to be using DNS to redirect traffic for specific
websites.
IPv6 Tests +
DNS support for IPv6
(?<http://n4.netalyzr.icsi.berkeley.edu/info_ipv6_dns.html>):
OK
IPv4, IPv6, and your web browser
(?<http://n4.netalyzr.icsi.berkeley.edu/info_ipv6_javascript.html>):
No IPv6 Support
IPv6 connectivity
(?<http://n4.netalyzr.icsi.berkeley.edu/info_ipv6_connectivity.html>):
No IPv6 Support
Host Properties +
System clock accuracy
(?<http://n4.netalyzr.icsi.berkeley.edu/info_system_clock.html>):
OK
Browser properties
(?<http://n4.netalyzr.icsi.berkeley.edu/info_browser_properties.html>):
OK
Uploaded data (? <http://n4.netalyzr.icsi.berkeley.edu/info_upload.html>):
OK
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