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[Help Needed] Block outgoing ping
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Topic: [Help Needed] Block outgoing ping (Read 438 times)
ubear
Newbie
Posts: 4
Karma: 0
[Help Needed] Block outgoing ping
«
on:
August 18, 2024, 03:33:34 pm »
Hello wise people!
I have the following setup:
LAN and 7 VLAN's on igb0
Primary WAN on igb1
Fallback WAN2 on igb2
Q1: I want to block ping from all LAN and VLAN's to any external addresses (WAN or WAN2) while preserving ping within my network.
My attempt for WAN: created an OUT rule on WAN that (PASS or BLOCK) IPV4 ICMP packets. both modes blocked the outgoing ping, WHY?
Q2: I want to enable outgoing ping from ONE particular host for speedtest. Adding such a rule (pass, from 192.168.60.10 to any, IPV4, ICMP) below or above the previously mentioned rule has no effect. Why?
Why block ICMP:
https://socfortress.medium.com/data-exfiltration-using-icmp-and-how-to-detect-it-69a799cca234
https://medium.com/@sam.rothlisberger/icmp-echo-request-data-exfiltration-f41f59fcf87a
https://github.com/martinoj2009/ICMPExfil
Why block on WAN-OUT:
Because I heve 8 internal networks. one rule to block all ICMP plus 7 rules to allow ICMP to other internal LAN's is 64 rules to write.
Many thanks
Uri
«
Last Edit: August 20, 2024, 11:57:51 am by ubear
»
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doktornotor
Hero Member
Posts: 709
Karma: 70
Re: Block outgoing ping
«
Reply #1 on:
August 18, 2024, 04:00:45 pm »
Dunno, I do not like breaking basic network diagnostics tools for people, such as ping, so don't have any such issue.
Just on a generic note, generally you want to block packets where they first hit the firewall (i.e., using the firewall rules that apply to the (VLANs). No point in letting them leave (V)LAN just to drop them on WAN later on.
For further assistance from someone else, I'd say attaching a screenshot of your firewall rules and posting the logs would help.
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[Help Needed] Block outgoing ping