Re: Gateway server experiencing degraded performance

[Andrew K Adams <akadams%psc.edu@localhost>]

I've looked at traffic with tcpdump, but there is so much in both
scenarios that I can't really say that one service, or a
packet-of-death is triggering the degraded state.  But thinking in
aggregate, if there was a way to monitor the average packets/sec the
gateway is forwarding, in both scenarios, I'd at least know for
certain that it is or is not my gateway (I guess it's conceivable that
by rebooting I'm tweaking state in Comcast's next-hop during DHCP
negotiation or something ...)


Andrew

On Sun, May 15, 2022 at 12:19 PM Andy Ruhl <acruhl%gmail.com@localhost> wrote:
>
> On Sun, May 15, 2022 at 7:52 AM Andrew K Adams <akadams%psc.edu@localhost> wrote:
> >
> > Hi, I’ve noticed a problem with my NetBSD server that I really could
> > use some help with.  The server is acting as my home router (gateway)
> > in ‘pass-through’ mode with Comcast Xfinity as the service provider.
> > The only functions/services enabled on the server are: ip-forwarding,
> > dhcp-client, and NTP.   And on the internal-facing lan: NAT, DHCP, and
> > SSH.  The internal network supports 5+ wired hosts & 10+ wireless
> > devices.  I currently have the 1Gig option with Comcast and when
> > things are operating as expected, I see from an internal (wired) host
> > 750mbs of throughput according to Comcast’s Xfinity speed test
> > website.  The problem is that performance doesn’t last.  In anywhere
> > from 3 weeks to 24 hours, my network performance (again, using the
> > same wired host measured by Xfinity’s speed test) will drop to ~20mbs.
> > And the change is clearly observable in all networking applications,
> > e.g., Netflix.  I’m querying here, though, because the fix I’ve found
> > is to reboot the server.  Upon reboot, I immediately go back to
> > 750mbs.  Hence, I’d like to figure out how to troubleshoot what on my
> > server is (eventually) degrading my network performance.
> >
> > The server is relatively new; I built it using an ASUS Mini ITX with
> > two onboard GigE ethernet ports.  Here’s some relevant dmesg output:
> >
> > [     1.000000] NetBSD 9.1 (GENERIC) #0: Sun Oct 18 19:24:30 UTC 2020
> > [     1.000000]
> > mkrepro%mkrepro.NetBSD.org@localhost:/usr/src/sys/arch/i386/compile/GENERIC
> > [     1.000000] total memory = 3457 MB
> > [     1.000000] avail memory = 3380 MB
> >
> > [     1.025286] wm0 at pci0 dev 25 function 0: I217 LM Ethernet
> > Connection (rev. 0x05)
> > [     1.025286] wm0: interrupting at msi2 vec 0
> > [     1.025286] wm0: PCI-Express bus
> > [     1.025286] wm0: 2048 words FLASH, version 0.13.4
> > [     1.025286] wm0: 0x6a4480<FLASH,IOH_VALID,PCIE,ASF_FIRM,AMT,WOL,EEE>
> >
> > [     1.025286] re0 at pci3 dev 0 function 0: RealTek 8168/8111 PCIe
> > Gigabit Ethernet (rev. 0x0c)
> > [     1.025286] re0: interrupting at msix4 vec 0
> > [     1.025286] re0: using 256 tx descriptors
> >
> >
> > And from ifconfig (note, I’ve removed my IP & MAC address from the output):
> >
> > iquitos# ifconfig -a
> > wm0: flags=0x8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
> >         capabilities=7ff80<TSO4,IP4CSUM_Rx,IP4CSUM_Tx,TCP4CSUM_Rx>
> >         capabilities=7ff80<TCP4CSUM_Tx,UDP4CSUM_Rx,UDP4CSUM_Tx,TCP6CSUM_Rx>
> >         capabilities=7ff80<TCP6CSUM_Tx,UDP6CSUM_Rx,UDP6CSUM_Tx,TSO6>
> >         enabled=0
> >         ec_capabilities=17<VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,EEE>
> >         ec_enabled=2<VLAN_HWTAGGING>
> >         media: Ethernet autoselect (1000baseT
> > full-duplex,flowcontrol,rxpause,txpause)
> >         status: active
> >         inet X.X.X.X/20 broadcast 255.255.255.255 flags 0x0
> >         Inet6 X%wm0/64 flags 0x0 scopeid 0x1
> > re0: flags=0x8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
> >         capabilities=3f80<TSO4,IP4CSUM_Rx,IP4CSUM_Tx,TCP4CSUM_Rx,TCP4CSUM_Tx>
> >         capabilities=3f80<UDP4CSUM_Rx,UDP4CSUM_Tx>
> >         enabled=0
> >         ec_capabilities=3<VLAN_MTU,VLAN_HWTAGGING>
> >         ec_enabled=0
> >         media: Ethernet autoselect (1000baseT full-duplex)
> >         status: active
> >         inet 10.19.34.1/24 broadcast 10.19.34.255 flags 0x0
> >         inet6 fe80::728b:cdff:febc:831b%re0/64 flags 0x0 scopeid 0x2
> > lo0: flags=0x8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 33176
> >         inet 127.0.0.1/8 flags 0x0
> >         inet6 ::1/128 flags 0x20<NODAD>
> >         inet6 fe80::1%lo0/64 flags 0x0 scopeid 0x3
> >
> >
> > I’m not sure what other information would be useful, just let me know,
> > and thank you in advance for help you can give me!
>
> Just a question, not a requirement, but have you looked at Wireshark
> traces comparing good performance vs. bad performance?
>
> It's just another way to find possibly find a problem. I'm sure
> someone else will have better ideas.
>
> Andy