ASUS Log – kernel: nf_conntrack: expectation table full

[UK Sentinel]

ASUS System Log Warning – kernel: nf_conntrack: expectation table full message

OK, so I upgraded my RT-AC86U to ASUSWRT-Merlin latest firmware RT-AC86U_384.14_0

I noticed, probable there from previous versions, the following System Log messages.

• Dec 16 13:16:17 kernel: nf_conntrack: expectation table full
• Dec 16 13:16:30 kernel: nf_conntrack: expectation table full

The “kernel: nf_conntrack: expectation table full” log message is causing many log messages to be created and after a reboot of the router, browsing does appear to slow after 15 minutes or so.

So after some research I found the following post on the Billion Forum which indicated the log message could be related to the Firewall.

As it happened, I had recently disabled IPv6 on my ASUS router, but had not disabled the IPv6 Firewall.

IPV6 Firewall is now disabled and no more – kernel: nf_conntrack: expectation table full log messages

This is why I both love and hate ASUSWRT and ASUSWRT-Merlin, the annoyance of the problems followed by the relief of the fix/remedy

P.S.  “I am getting to old for this kind of crxp” ;-)

 

 

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[UK Sentinel]

2 hours later the kernel: nf_conntrack: expectation table full log message has returned ;-(

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[Grisu]

UK Sentinel wrote:

This is why I both love and hate ASUSWRT and ASUSWRT-Merlin, the annoyance of the problems followed by the relief of the fix/remedy

P.S.  “I am getting to old for this kind of crxp” ;-)

It keeps you young!

One Asus router and you have a full time job …

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[UK Sentinel]

So two years later I plugged back in my ASUS RT-AC86U a few days ago which is now running latest ASUSWRT-Merlin 386.7_2 and noticed that the ASUS Log was still showing the following log message and experienced internet access issues every couple of days.

 kernel: nf_conntrack: expectation table full

Could not understand why this was still an issue some two+ years later so had a good look online and found nothing useful, so decided to have a chat with ASUS to get this sorted…. or at least a way around the problem for the RT-AC86U.

In the ASUS Log – kernel: nf_conntrack: expectation table full – message appears due to the large number of connections on the LAN side by LAN devices/ applications, maybe from Gaming, Data mining etc.

Currently, I am trying the below cmd suggested by ASUS to see if this problem re-occurs and a couple of days is the key marker for myself.

nvram set ct_expect_max=1024
nvram commit
reboot

(the CMD will survive a reboot but not a factory reset)

You can execute the following command through Telnet / Putty etc. and should work for both Stock ASUSWRT as well as ASUSWRT-Merlin.

 

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[UK Sentinel]

24 hours later and still no  kernel: nf_conntrack: expectation table full – log message

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[UK Sentinel]

Another 24 hours later and still no  kernel: nf_conntrack: expectation table full – in system log

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[UK Sentinel]

Another 2 more days have passed (4 in total) and still no  kernel: nf_conntrack: expectation table full – in system log

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[UK Sentinel]

For those that are interested, to find what your original (stock) nf_conntrack: expectation table value is,   using   Telnet / Putty etc. type the below CMD.

‘Note: my RT-AC86U was 108 and is now 1024’

 

CMD:

cat /proc/sys/net/netfilter/nf_conntrack_expect_max

 

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   CMD-for-nf-conntrack-expectation-table-value-.png
   

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[UK Sentinel]

Note:

When I spoke with ASUS, they did say that Yes, it may occur on other similar model too and for some high end model with 1GB memory, they have set that value to 4096 by default already.

 

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[UK Sentinel]

Another 3 more days have passed (7 in total) and still no  kernel: nf_conntrack: expectation table full – in system log.

Not going to monitor this event any further as 7 days is good for myself without any internet access pauses etc.

Problem solved

 

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[nzhome]

I have a family of 5 in 2024.  The number of devices clearly overtakes the capabilities of this router..  until your solution above. thank you!

this forum thread is the number 1 hit on google for this error message. so thank you very much for the solution OP, and Asus Support.

ASUS RT-AC86U Operation Mode:Wireless router Firmware Version:3.0.0.4.386_46092

Sep 4 12:11:02 kernel: nf_conntrack: expectation table full
Sep 4 12:11:03 kernel: nf_conntrack: expectation table full
Sep 4 12:11:06 kernel: nf_conntrack: expectation table full
Sep 4 12:11:07 kernel: nf_conntrack: expectation table full

I will report back in 7 days time.

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[UK Sentinel]

Welcome to UKTechHub and good to hear this was useful for yourself

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[UK Sentinel]

. nzhome Said:

I have a family of 5 in 2024.  The number of devices clearly overtakes the capabilities of this router..  until your solution above. thank you!

 

 

I will report back in 7 days time.

Did you have any more issues with kernel: nf_conntrack: expectation table full ?

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[Anonymous]

hi my friend, i am getting 1 issue in my fiber router it has mtk chipset and issue is that internet is not browsing if i am connecting wan with pppoe user name password , dns ping is coming also sometimes google.com ping is coming but on browser browsing is not hapenning , i diagnosed many things in this and found the same error nf_conntrack: expectation table full in my router if i connect any lan cable or wifi to access internet  and i am unable to troubleshoot this issue , could you have me out

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[UK Sentinel]

Welcome, which router model is it ?

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