Thunderbird + Gmail + my LAN = SLOW e-mail [SOLVED]

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Reorx
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Thunderbird + Gmail + my LAN = SLOW e-mail [SOLVED]

Post by Reorx » Wed Feb 11, 2015 9:25 pm

My ISP is a local cable company (Comcast). My home LAN/internet connection is a Linksys EA9600 AC1900 router + an Arris MT822 cable modem. Once set up and configured correctly, my internet connection has worked without problems with this type of performance >
Internet_Performance2.png
I have 2 laptops (LM17 Cinnamon 64 bit) and a smart phone (Android) that access Gmail over the connection. Over the last several weeks, the Gmail performance has fallen off dramatically. On my laptop, I have 2 Gmail accounts - 1 is POP and 1 is IMAP - BOTH run very slowly. My wife (the other laptop and smart phone) has 1 Gmail IMAP account - It also runs very slowly... so slowly the phone frequently "times out" before flipping the mail. We both also have other e-mial accounts from a local phone company that (all POP mail) function as they always have (good performance). The Gmail performance “glitch” has these characteristics – from opening Thunderbird to Gmail arrives takes about 2.5 minutes. Sending mail on the Gmail accounts also takes 2 to 3 minutes if I just click send and wait... but if I click send and then cancel the send and then resend, the second send happens in less than 5 seconds – every time.

Another symptom is that Mint Update also runs in a similar slow fashion. When updates are available, If I click “install”, Mint Update will try to D/L the updates but makes no progress for a few minutes... then (suddenly) the updates will come down at expected speeds and install normally. This seems to be “new” and seems to parallel the Gmail slow down. I have no explanation why the 2 would be related but they seem to be. This “problem” also has been occurring on my wife's laptop as well.

The internet seems otherwise unaffected. I did some Googling and tried a few things:
1) I configured my router to use different DNS servers (OpenDNS) with no effect (Comcast is notorious for “sluggishness”).
2) I temporarily disabled my router firewall with no effect.
3) I rebooted the router with each of the above changes and with turning the firewall back on with no effect.

My office laptop (also running LM17C64) is not having any of these problems so – I recently took the phone and my home laptop to my office. Tried the problematic operations and all problems are non-existant at my office. Everything (Mint Update, Gmail D/L, and Gmail send) works exactly as it is supposed to – NO slow downs, lags, or “pauses”. The router at my office is a Linksys WRT54G (802.11g)... yeah, it's about 12 years old (give or take) but it still works just fine for my small office LAN. I am not sure what the cable modem is as it was supplied by my office ISP (Comcast)... so I went back home...

I tried powering down my cable modem (hadn't done this before)... I also powered down the router while I was at it... waited for a minute or 2 and then powered everything back up... and the problems are unchanged. I also tried wired vs. wireless... no difference.

I think the problem is not really a Mint problem but seems to be a hardware/firmware/configuration problem. I have never encountered anything even remotely resembling this situation...

SO, my questions are these:
Have any of you seen anything like this before? And, if so, do you have any recommendations regarding where to start looking or something to do in an attempt to fix it?
Last edited by Reorx on Sat Mar 21, 2015 10:46 am, edited 1 time in total.
Full time Linux Mint user since 2011 - Currently running LM19 Cinnamon.

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Re: Thunderbird + Gmail + my LAN = SLOW e-mail

Post by Reorx » Wed Feb 18, 2015 10:35 am

UPDATE:

The problem persists but I think I am a little closer to a solution. I did some searching and reading... and tried something else >>>

When I plug my computer directly into my cable modem (@ home) using a cat 5 wire (bypassing the router entirely), the problems vanish. Everything works perfectly. So, it seems as though the problem is somewhere in my router. I will continue to dig into this and with a little luck, I'll be posting a solution soon...
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Re: Thunderbird + Gmail + my LAN = SLOW e-mail

Post by Reorx » Sat Feb 21, 2015 10:51 pm

UPDATE #2:

Something I read on the Linksys support forum suggested >>> Update firmware > reset to factory defaults > reconfigure router... so I tried it. The first try I did the reconfig completely manually. The resulting configuration showed no improvement in the problems. I plan to try another attempt or 2 using somewhat different methodologies to see if that will have any effect... <to be continued...>
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Re: Thunderbird + Gmail + my LAN = SLOW e-mail

Post by Reorx » Sun Feb 22, 2015 12:19 am

gmilo2 wrote:...I would expect in your case that you would have slow internet all around, and not just with email...
No. Read 1st post in the thread. I describe (in some detail) what the problems are.

After the process of update, reset, & reconfigure, the performance looked like this (a few hours ago) >>>
Performance_2-21-2015.png
(this is exactly what I expect from my ISP based on the service I am paying for)
gmilo2 wrote:...Linksys wanted you to update firmware and then reset to factory defaults?...
No, not Linksys but rather someone in a thread on their support forum... and the thread wasn't mine but I found it searching...
gmilo2 wrote:...That sounds like it would just take you right back to the firmware that was on it from the factory, defeating the purpose.
The (original) "factory firmware" was an update or 2 (or so) ago... I might eventually try rolling back the firmware as, originally, everything worked perfectly...
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Re: Thunderbird + Gmail + my LAN = SLOW e-mail

Post by Reorx » Sun Feb 22, 2015 2:30 am

gmilo2 wrote:...Might be worth a call to Linksys...
Might be... :mrgreen:
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Re: Thunderbird + Gmail + my LAN = SLOW e-mail

Post by Reorx » Sat Mar 21, 2015 10:45 am

Was reading the Mint forums this morning and stumbled into the solution for this problem...

The solution is to disable IPv6

The thread where I found the solution >>> http://forums.linuxmint.com/viewtopic.php?f=90&t=191127 (Thank you Wrek)

As stated above, I have several devices connected to my LAN. To test the solution on my personal laptop, I edited and restarted sysctl.conf. IT WORKED - YES!!! All of my above described problems vanished.

On a Mint machine, disabling IPv6 is done like this >>>

Code: Select all

gksudo gedit /etc/sysctl.conf
Add this text to the bottom of sysctl.conf then save and close >>>

Code: Select all

# IPv6 disabled
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1
restart sysctrl >>>

Code: Select all

sudo sysctl -p
Alternative solution: I edited my router configuration to disable IPv6 to see if that would fix the problem on all the devices on my LAN in 1 fell swoop - IT WORKED! :D All the devices on my LAN now work perfectly laptops and smart phones alike.

Final thought: The slowness was ultimately caused by IPv6 functionality problems. Disabling IPv6 fixes the problem. You can disable IPv6 at the level of the device or at the level of the router with equal effectiveness for devices that are stationary. If a device is portable and occasionally connects to other LANs, it might be wise to disable IPv6 at the level of the device.

I hope this solution is helpful to others experiencing similar problems...

Enjoy the Mint! :mrgreen:
Full time Linux Mint user since 2011 - Currently running LM19 Cinnamon.

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