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Date:      Sun, 4 Oct 2020 22:07:09 +0200
From:      Miroslav Lachman <000.fbsd@quip.cz>
To:        l.m.v.breda@xs4all.nl, freebsd-pf <freebsd-pf@freebsd.org>
Subject:   Re: PF states limit reached
Message-ID:  <e79311cd-cfca-8356-1915-8db190a69f24@quip.cz>
In-Reply-To: <000801d6996d$81b5ab20$85210160$@xs4all.nl>
References:  <c7911e9d-eb9f-dde2-dcd4-518d98299954@quip.cz> <VE1PR03MB56297DCDECE8D7514E6907E1A0310@VE1PR03MB5629.eurprd03.prod.outlook.com> <489adbd3-4400-0cf8-31f1-45509af31925@quip.cz> <VE1PR03MB5629E1B9AA2C625F59AD03F2A0310@VE1PR03MB5629.eurprd03.prod.outlook.com> <9c2bc3f6-0420-fe79-ae36-8a62511f71b2@quip.cz> <000801d6996d$81b5ab20$85210160$@xs4all.nl>

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On 03/10/2020 12:11, l.m.v.breda@xs4all.nl wrote:
> Miroslav,
> 
> I saw your mails. First thing I thought when I dis see your mails is "** What is going on, on that network!! **".
> 
> I can be wrong, but are you really sure that there is no malware of any kind, using your network, causing the problems !!

I can never be 100% sure but as far as I can tell there is no malware on 
this network. We have rented 19" rack in DC with /25 IP addresses and 
only this VM in question had this problem. No anomalies seen on the 
network (no unusual traffic, Apache workers and so on)

> I would never change my firewall, to cope with strange things !!
> Just making things less secure!

I don't think PF without state tracking would be less secure. I am not 
an expert in this area but as I can see it the states can be target for 
DoS and I do not think the state tracking is useful if we already have 
policy "open for all outgoing traffic". Maybe I am wrong. I was thinking 
about "no state" for a long time regardless of this current issue.

I don't know what was causing this problem but it disappeared after VM 
reboot. So I think it was some issue on OS / kernel side. I hope it will 
not repeat again but if it will I will let you know.

3 hours after reboot everything seems fine:

# pfctl -s states | wc -l
       55

# pfctl -s info
Status: Enabled for 0 days 03:06:21           Debug: Urgent

Interface Stats for em0               IPv4             IPv6
   Bytes In                       180884551                0
   Bytes Out                     1182768426                0
   Packets In
     Passed                          685980                0
     Blocked                           1471                0
   Packets Out
     Passed                         1008493                0
     Blocked                            124                0

State Table                          Total             Rate
   current entries                       63
   searches                         1696122          151.7/s
   inserts                            31427            2.8/s
   removals                           31364            2.8/s
Counters
   match                              33014            3.0/s
   bad-offset                             0            0.0/s
   fragment                               0            0.0/s
   short                                  0            0.0/s
   normalize                              0            0.0/s
   memory                                 0            0.0/s
   bad-timestamp                          0            0.0/s
   congestion                             0            0.0/s
   ip-option                              0            0.0/s
   proto-cksum                            0            0.0/s
   state-mismatch                         8            0.0/s
   state-insert                           0            0.0/s
   state-limit                            0            0.0/s
   src-limit                              0            0.0/s
   synproxy                               0            0.0/s
   map-failed                             0            0.0/s

Kind regards
Miroslav Lachman



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