Re: dtrace to trace incoming connection not suceeding ?

> On 12. Nov 2021, at 14:09, Kurt Jaeger <pi@FreeBSD.org> wrote:
> 
> Hello,
> 
> I'm trying to investigate tcp-179 connection issues with the
> local frr setup. See below for more background.
> 
> The question is: What can I do to find the cause of the failing
> connection ? Is there a way to trace the incoming packet to see
> if it ever ends up at bgpd process ?
> 
> Background: a fbsd 13.0p4 amd64 box, with a frr-7.4_4 (or 7.5.1_3)
> fails to act on incoming ipv4 tcp 179 connections.
> 
> The bgpd daemon of frr listens on port 179:
> 
> frr      bgpd       96061 20 tcp6   *:179                 *:*
> frr      bgpd       96061 21 tcp4   *:179                 *:*
> 
> Incoming packets can be seen with tcpdump on the dest host:
> 
> # tcpdump -i vlan500 -n -s 1500 port 179 and host <source-host>
> tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
> listening on vlan500, link-type EN10MB (Ethernet), capture size 1500 bytes
> 13:53:13.795162 IP <source>.12274 > <dest>.179: Flags [S], seq 62227917, win 65535, options [mss 1460,nop,wscale 9,sackOK,TS val 2870882787 ecr 0], length 0
> 
> But: No connection is established 8-(
> 
> The basic ipfw firewall is active, but
Does it work, if you disable ipfw?

Best regards
Michael
> 
> -- 
> pi@FreeBSD.org         +49 171 3101372                  Now what ?
>