| 1 |
> It's not the ICMP that is being prohibited. |
| 2 |
|
| 3 |
Understood, that's clear from the packet trace. |
| 4 |
|
| 5 |
> is an ICMP "host unreachable" response from .250. The extended reason |
| 6 |
> for the unreachability is that there is an administrative policy |
| 7 |
> preventing the traffic. It almost certainly *is* a firewall that's |
| 8 |
> preventing this, one with a REJECT target, as REJECT specifies to |
| 9 |
> return an ICMP unreachable packet. |
| 10 |
|
| 11 |
Most firewalls i've seen send a spoofed TCP reset, not an ICMP when |
| 12 |
rejecting TCP. However, iptables can do either. I have run iptables -F |
| 13 |
and the tables are shown as clear with iptables -L. |
| 14 |
|
| 15 |
proxy vhosts.d # iptables -L |
| 16 |
Chain INPUT (policy ACCEPT) |
| 17 |
target prot opt source destination |
| 18 |
|
| 19 |
Chain FORWARD (policy ACCEPT) |
| 20 |
target prot opt source destination |
| 21 |
|
| 22 |
Chain OUTPUT (policy ACCEPT) |
| 23 |
target prot opt source destination |
| 24 |
|
| 25 |
Chain fail2ban-SSH (0 references) |
| 26 |
target prot opt source destination |
| 27 |
|
| 28 |
Chain fail2ban-apache (0 references) |
| 29 |
target prot opt source destination |
| 30 |
proxy vhosts.d # |
| 31 |
|
| 32 |
> I suggest that you look more |
| 33 |
> closely at the firewalling on .250. If there is definitely no |
| 34 |
> firewalling going on (ie iptables -nvL shows only default policies and |
| 35 |
> the default is ACCEPT for INPUT and OUTPUT chains) then could there be |
| 36 |
> an intervening network device? |
| 37 |
|
| 38 |
The devices are connected, there's only a switch between them (a |
| 39 |
billion ADSL router). |
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