Arch Linux

derbernd

Member

Registered: 2022-09-19

Posts: 3

IP blocked

Hello,
I have a problem. A specific IP is blocked so I cannot access the remote via SSH. From another computer everything works.

I have not knowingly installed any firewall or added any rule in ip tables.

What could be the reason?

Thx

seth

Member

Registered: 2012-09-03

Posts: 60,805

Re: IP blocked

What could be the reason?

Something.
=> https://bbs.archlinux.org/viewtopic.php?id=57855

* what IP
* are all systems in the same segment
* how do you determine that it's "blocked"
* can you ping the IP
* can you nmap it (and what's the result)
* "iptables -nvL" / "nft list ruleset"

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derbernd

Member

Registered: 2022-09-19

Posts: 3

Re: IP blocked

- no ping posible
-

nmap 172.*.*.*    
Starting Nmap 7.92 ( https://nmap.org ) at 2022-09-19 15:40 CEST
Note: Host seems down. If it is really up, but blocking our ping probes, try -Pn
Nmap done: 1 IP address (0 hosts up) scanned in 3.08 seconds

iptables -nvL
Chain INPUT (policy ACCEPT 472K packets, 462M bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain FORWARD (policy ACCEPT 1217 packets, 225K bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain OUTPUT (policy ACCEPT 167K packets, 5102M bytes)
 pkts bytes target     prot opt in     out     source               destination     

ssh *@172.*.*.*
ssh: connect to host 172.*.*.* port 22: No route to host

seth

Member

Registered: 2012-09-03

Posts: 60,805

Re: IP blocked

No route to host

Is not "blocked"

ip a; ip r

nmap 172.*.*.*

Is that anything beween 172.16. 0.0 and 172.31. 255.255 ? Because then it's a private segment and there is no point in this obfuscation dance.

are all systems in the same segment

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derbernd

Member

Registered: 2022-09-19

Posts: 3

Re: IP blocked

The IP address is anonymised and lies within the mentioned IP range.

The computers are located in different subnets.

I have found that there is a network bridge. The IP matches the port range. However, I have no idea why this bridge is there. Can I see which service has created it? I deleted the brides and now everything is working.

Last edited by derbernd (2022-09-19 14:32:29)

seth

Member

Registered: 2012-09-03

Posts: 60,805

Re: IP blocked

The IP address is anonymised and lies within the mentioned IP range.

Yeah, that's nonsense.
https://de.wikipedia.org/wiki/Private_I … ssbereiche (taking a guess from your nick)

The computers are located in different subnets.

That's gonna be a problem.

Please post the requested output from the system where stuff doesn't work, from the system where it works and reveal the target IP.
You're not disclosing anything that's meaningful to anyone outside your LAN.

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