# Freebsd 13. Traffic speed degradation.



## ayfom (Apr 28, 2021)

Hello.
After upgrade system to Freebsd 13 I noticed traffic speed degradation in a communication with one of the host in local network.(and with this host only.). Pcap file of this communication in the attachment(dup_ack_dump.pcapng). There are a lot of duplication of packets with ACK flag and retransmission. As I understand system duplicate outgoing packets with ACK flag when incoming packets come in wrong order. Freebsd host (192.168.1.137) received packets #40-44 which came in right order, but system haven't acknowledged receiving of these packets and  sent Selective Ack without these packets (packet #49). All of these packets were retransmitted after that. And this happened again and again. I've attached similar communication, but from VM(bhyve) with Freebsd12(ok_dump.pcapng). Everything's fine there.

I'd really appreciate if somebody help me to understand what happens.


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## ayfom (May 6, 2021)

I've seen 'tcpflags 0x10<ACK>; tcp_do_segment: Timestamp missing, segment silently dropped' records in logs after setting up net.inet.tcp.log_debug=1. Indeed, packets #40-44 don't have timestamps which hosts had been negotiated before and it's reason why they were dropped(not acknowledged). FreeBSD13 has a new option net.inet.tcp.tolerate_missing_ts. Setting up net.inet.tcp.tolerate_missing_ts=1 solve the problem. 
PS. But there is still question why counter party host sends packets without timestamps.


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## Steffen (May 7, 2021)

I observe the same problem, but for all clients using Unifi APs in the communication path. Clients are laptops, mobiles, etc with different operating systems.


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## disgrace (Jul 1, 2022)

same problem. had no issues with freebsd 11 as a guest VM on a server. after installing freebsd 13, i constantly get interface errors on incoming traffic only (outbound appears unaffected). incoming errors build until the session freezes the the box lags, at which point i can cycle the interface with the following to get it back stable (but if the high traffic continues, it will eventually freeze again. sometimes within 10 seconds, sometimes in 90 seconds, etc etc)

/sbin/ifconfig le0 down
/sbin/ifconfig le0 up

i am running a bandaid script that detects interface errors and attempts to cycle the interface. its not perfect...


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## Deleted member 70435 (Jul 1, 2022)

ayfom said:


> Hello.
> After upgrade system to Freebsd 13 I noticed traffic speed degradation in a communication with one of the host in local network.(and with this host only.). Pcap file of this communication in the attachment(dup_ack_dump.pcapng).


To preserve everyone's security, place these files. .txt


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## disgrace (Jul 31, 2022)

identified my issue... possibly unrelated to OP

noticed my BSD 13x installation (via VMWare workstation 16x) was using le0 as its virtual interface
compared to my previous BSD 11x installation (via VMWare workstation 16x) which was using em0 as its virtual interface

once i shut down the VM, edited the .vmx configuration file to include the below line, i no longer have any interface errors and my networking is stable again:
ethernet0.virtualDev = "e1000"


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