Firefox display of LinkedIn slow on Fedora 10

[Michael Eager]

Bill Davidsen wrote:
> Michael Eager wrote:
>> Hi --
>>
>> When I try to open a page on LinkedIn in Firefox or
>> Konqueror, it takes forever to display.  Often, the
>> session times out before the page is shown.  I have
>> not noticed any other sites which have similar problems.
>>
>> A Google search shows that a number of people have encountered
>> similar problems.  There were conjectures that the problem
>> has to do with routers or network settings.  There are a few
>> suggestions to reduce the TCP MTU size, and some people
>> claimed this fixed their problem.  When I followed these
>> suggestions, it doesn't improve display of LinkedIn pages,
>> but it did screw up display of other sites.
>>
>> On a Windows XP system running under VMware on the same
>> hardware, Firefox displays LinkedIn pages with no delay.
>>
>> Since the network connection and router is the same,
>> it's not a problem with the physical hardware.  Since
>> the same problem appears on both Firefox and Konqueror,
>> it's not a problem with the browser display engine.
>>
>> Anyone have a suggestion how to eliminate this annoyance?
>>

Thanks for the suggestion.

> MTU sounds good, the usual "real cause" is some router not passing or 
> honoring the "can't fragment" ICMP. If you are running from a VM, behind 
> a tunnel, etc, etc, this might be your problem, and since there's a 
> simple solution it's worth a try.

Actually, the WinXP system running in the VM works OK; the
host Linux system is the one that fails.  The VM is accessing
the NIC in promiscuous mode.  The same routers should be in place
for both VM and host.

> Look at the "mss M" section of the "man route" output, and it explains 
> this better. Using the route command you can set a route to the problem 
> site, via your default router, and only for that route use a smaller 
> MTU. So "mss 1400" would be part of the command line.

Tried host route:

# route -v add -host linkedin.com mss 1400 gw gateway dev eth0
# route -e
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
www.linkedin.co gateway         255.255.255.255 UGH    1400 0          0 eth0
172.16.160.0    *               255.255.255.0   U         0 0          0 vmnet1
192.168.20.0    *               255.255.255.0   U         0 0          0 eth0
192.168.238.0   *               255.255.255.0   U         0 0          0 vmnet8
link-local      *               255.255.0.0     U         0 0          0 eth0
default         gateway         0.0.0.0         UG        0 0          0 eth0

Also tried network route:

# route -v add -net 64.74.98.0 netmask 255.255.255.0  mss 1400 gw gateway dev eth0
# route -e
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
172.16.160.0    *               255.255.255.0   U         0 0          0 vmnet1
192.168.20.0    *               255.255.255.0   U         0 0          0 eth0
64.74.98.0      gateway         255.255.255.0   UG     1400 0          0 eth0
192.168.238.0   *               255.255.255.0   U         0 0          0 vmnet8
link-local      *               255.255.0.0     U         0 0          0 eth0
default         gateway         0.0.0.0         UG        0 0          0 eth0

Neither appear to make any difference.  I also shrank MTU down to 1000
to see if that helped.  Same result.

One interesting aspect is that some of the LinkedIn pages come up fast,
others hang.  Firefox thinks it's waiting for www.linkedin.com.  I could
run a sniffer to see if it really is accessing the IP address with the
reduced MTU.



-- 
Michael Eager	 eager at eagercon.com
1960 Park Blvd., Palo Alto, CA 94306  650-325-8077