Gentoo Archives: gentoo-user

From: Alec Ten Harmsel <alec@××××××××××××××.com>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] [OT] Routing Problems
Date: Sat, 18 Oct 2014 18:13:30
Message-Id: 5442ADC3.9070404@alectenharmsel.com
In Reply to: Re: [gentoo-user] [OT] Routing Problems by Mick
1 On 10/18/2014 12:37 PM, Mick wrote:
2 > On Saturday 18 Oct 2014 16:38:52 Alec Ten Harmsel wrote:
3 >> On 10/18/2014 04:06 AM, Mick wrote:
4 >>> What do the router logs say?
5 >> DD-WRT is not very informative. It only has system-type stuff in
6 >> /var/log/messages, nothing LAN-related.
7 > As James suggested, if you have SSH or telnet access to the router run arp to
8 > see what the arp tables include. Also ping the server from the router to see
9 > if you get any responses. I expect that these will not reveal anything
10 > untoward, but it is best to follow a process of elimination a step at a time.
11
12 All fine here; pinging from router to server works, and the ARP table
13 has entries for both desktop and server.
14
15 >
16 >>> Have you captured any packets on both ends and in between?
17 >> Capturing packets on my desktop shows strange behavior. When I ping my
18 >> server (kwopper), my desktop (greenbeast) starts generating a bunch of
19 >> ARPs, none of which get answered.
20 > Only to state the obvious, that this is not the expected behaviour. Are you
21 > sure that the server firewall isn't configured to only allow connections from
22 > your laptop and/or drop arp packets to avoid arp attacks? What happens when
23 > you disable the firewall?
24
25 Firewall is completely disabled on the server, as is SELinux.
26
27 >
28 >> When my laptop pings kwopper, the
29 >> first ARP is answered instantly and the pings succeed. Pinging from
30 >> kwopper is the same; instantly finds and connects to my laptop, but my
31 >> desktop does not see any ARPs or ICMPs from kwopper.
32 > Using arpscan and arping between desktop and server you should be able to find
33 > out what is happening, but I suspect something to do with the server
34 > configuration.
35 >
36
37 arpscanning the entire subnet results in 3 responses, with 2 being
38 displayed and 1 being dropped by the kernel. arpping, even with -D and
39 -U, returns nothing.
40
41 I have no idea what's going on. I think what I'm gonna do is install my
42 old router behind the new router and plug in all my device to that one
43 and see if it works, because I absolutely need my desktop and server to
44 be able to reach each other.
45
46 Alec

Replies

Subject Author
Re: [gentoo-user] [OT] Routing Problems Alec Ten Harmsel <alec@××××××××××××××.com>
Re: [gentoo-user] [OT] Routing Problems Mick <michaelkintzios@×××××.com>