what do some log mean?

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john_7
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Joined: Sun Jul 24, 2011 6:04 pm

what do some log mean?

Post by john_7 » Sun Jul 24, 2011 6:06 pm

I have a new 7800N and am a bit confused with some of the messages being logged in the system log and why when I tested the system firewall with a number of on line tests (it passed all of them) nothing was in the firewall log?
The messages that lose me are:-
daemon UPNPD[1655]: received signal 15, good-bye
and after one of my regular loss of connexions (always get them a poor line),
daemon pppd[599]: Couldn't increase MTU to 1500
The MTU one loses me as I have set MTU at the BT line recommended 1458

nozzer
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Joined: Wed Jul 20, 2011 4:34 pm

Re: what do some log mean?

Post by nozzer » Mon Jul 25, 2011 9:30 am

The "signal 15" message is a shout from the operating system to shut down a process if it's not "happy" with what's going on. Are you running any Boinc applications by any chance?

I was under the impression that a standard BT line running under PPPoA should have MTU set at 1500.

john_7
Posts: 10
Joined: Sun Jul 24, 2011 6:04 pm

Re: what do some log mean?

Post by john_7 » Mon Jul 25, 2011 7:46 pm

nozzer wrote:The "signal 15" message is a shout from the operating system to shut down a process if it's not "happy" with what's going on. Are you running any Boinc applications by any chance?

I was under the impression that a standard BT line running under PPPoA should have MTU set at 1500.
I have no idea if I am running any Boinc applications, some of the logs are when the PC has been off over night and as Billion been rebooting due to my poor line.

I have run TCPOptimizer and it come up with 1456 after running it. I have changed the 7800N over to 1500 and just changed the laptop to 1456.
http://myspeed.visualware.com which had been unhappy with quality on a new test is happy so I will see how it goes.
PS am I right that MTU between laptop and modem and modem and network can be better different as I had had them the same before. I had done a lot of manual MTU testing (trying to reduce our line issues) and they a

andyjrobinson
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Re: what do some log mean?

Post by andyjrobinson » Tue Jul 26, 2011 10:58 am

Hi,

Just thought I would pop in here and try and answer your questions also.

daemon UPNPD[1655]: received signal 15, good-bye

As far as I know and what I can see and determine, this appears to be the UPNP daemon closing a connection that has been opened either by the OS or an application that you are using.

daemon pppd[599]: Couldn't increase MTU to 1500

This is basically telling you that the router cannot increase the MTU value to 1500, mainly because you have set this manually to 1458, which is the recommended value for BT broadband.

MTU values of 1500 are mainly only used on some ADSL2+ services and Cable services, such as those from Virgin Media.

Hope this helps.
Best Regards,
Andrew Robinson.

nozzer
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Re: what do some log mean?

Post by nozzer » Tue Jul 26, 2011 7:33 pm

You might find this helpful.......

http://www.kitz.co.uk/adsl/MTU.htm

It explains that the MTU of the router must not be set at a lower value that the PC's MTU. MTU discovery, if active, will automatically get Windows to seek the best MTU for the PC to request data from a host, but you're safest to set the router's MTU to 1500. That way the PC will always request a data transmission value lower than the router is set to.

andyjrobinson
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Re: what do some log mean?

Post by andyjrobinson » Tue Jul 26, 2011 9:06 pm

Hi,

No that information is incorrect.

It just means that the PC will not be able to send packets at the size of anything above the MTU of the router.

You must set the MTU on the router and the PC for it to have an effect.

To set the MTU on Windows Vista/Seven, follow the below information:
Speedguide.net wrote:It is sometimes useful to view and set the MTU value for a specific network interface manually. To view a list of active network interfaces and their MTU values in Vista using netsh, open command prompt as administrator and execute the following command:

netsh interface ipv4 show subinterface

You will be presented with a list of interfaces, and their respective MTU values as follows:

To change the MTU value of a specific network card, type the following in command prompt:
netsh interface ipv4 set subinterface "network interface name" mtu=#### store=persistent

Where "network interface name" is your specific network adapter name as obtained above (or viewable under Network adapters), and mtu=#### is the desired MTU value.

For example, if the name of your network card is "Wireless Network Connection" and you'd like to set its MTU to 1500, you'd have to type:

netsh interface ipv4 set subinterface "Wireless Network Connection" mtu=1500 store=persistent

Note: The maximum MTU value is usually 1500, and up to 1492 for PPPoE connections.
If you have an MTU higher on the PC set to higher than what is set on the router, or what the ISP network is capable of, then packets become fragmented, and have to be re-transmitted since it is unable to send the packet in the size your PC is set to send. This causes overhead, much of which you probably wouldn't see by the eye, but can make a difference for online gaming and other time-crtitical online tasks.

Automatica MTU discovery, PMTU is enabled by default on Windows Vista and Seven as far as I can remember, however the discover does not discover the MTU from the ISP network, it is discovered from the Customer Premise Equipment, like the ADSL or Cable router or a Cable modem if no router is present. And from experience, routers and modems provided by ISP's always come with the wrong MTU settings anyway, which is why it is always a good idea to always optimize your network settings for that of the ISP when possible.
Best Regards,
Andrew Robinson.

nozzer
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Re: what do some log mean?

Post by nozzer » Wed Jul 27, 2011 8:54 am

As far as I can see that's exactly what the article and I said! Set the MTU on the router NO LOWER than the PC's MTU, ie same as or higher. Hence no fragmentation. The PC's setting should restrict the MTU properly.

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