Re: Policy-based routing for packets originating from local machine ('reinject' packets back into kernel?)

On Sunday 22 July 2007, m_wlist@xxxxxxxxxxxx wrote:
At the moment I'm trying to get that working with netgraph's ngeth
interfaces. But they seem to behave in some really weird way.
Details:
# ifconfig ngeth0 10.42.42.1 netmask 255.255.255.250

Netmask 255.255.255.250 looks weird to me. Something like this is really
unusual. What does ifconfig ngeth0 show?

Oh. Yes, that was a typo in command that I've copypasted here.
Thank you for pointing to that.

# ngctl connect ngeth0: ngeth1: lower upper
# ngctl connect ngeth1: ngeth0: lower upper
('tcpdump -ni ngeth0' on other terminal for great justice)
# ping 10.42.42.2
(here after some delay I get 'host is down' messages with no output from
tcpdump).
# ping 10.42.42.5
(broadcast address, gives nothing from ping, and 'blal blah 10.42.42.1 >
10.42.42.5: ICMP echo request, blah' from tcpdump)
(here i change tcpdump from ngeth0 to ngeth1)
# ping 10.42.42.2 and # ping 10.42.42.3
give 'host is down' from ping and nothing from tcpdump
# ping 10.42.42.4
(LOL WUT!) still gives 'host is down' from ping, but tcpdump -ni ngeth1
gives 'arp who-has 10.42.42.4 tell 10.42.42.1'!

That raises two questins:
1) Wtf is going on?
2) How to make ngeth just send ip packet, avoiding that arp stuff (or is
there any other virtual interface devices available that do that)?


I can't comment on these question, but my recommendation would be to
choose
more usual mask - if it's not a typo, this could cause various interesting
errors.

Now It looks more sane -- arp messages appear on trying to ping every
(except first that belongs to ngeth0) ip in that subnet.
So the second question is still open.

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