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Questions tagged [firewall]

For questions about or relating to firewall operations, configuration and troubleshooting.

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Difference between firewall and ACL

I have found many answers to this question, none of which satisfy me due to lack of detail. Can someone please explain in detail what is a firewall and what is its purpose, and what is an ACL and what ...
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0 votes
0 answers
11 views

Suspected BGP Flowspec blackholing [closed]

I'm having the following problem: https://api.kryptex.org is unavailable for random users in Russia no consistency within the same ISP in the same city When unavailable: mtr --tcp --port 443 api....
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1 vote
3 answers
49 views

What is the difference between having a firewall inside vs outside the network?

I am trying to better understand the firewall's placement for a secure & nominal operation with efficient traffic flow. The Question: What would the use case scenario be for firewall outside vs. ...
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0 votes
1 answer
50 views

TCP segment with flags ACK, PSH, URG

Can a TCP data segment with a 1 byte length have, at the same time, the flags ACK, PSH, URG set ? Is it conform or not to the TCP protocol ? Thank you.
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1 vote
1 answer
40 views

ARP cache in firewalls and difference from an end point device

Imagine a device A (192.168.32.5/24). Then two hosts, B and C, connected to the same interface (through a switch) having the same IP address (192.168.32.8/24) configured statically. No fancy tools/...
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0 votes
2 answers
102 views

Inherent flaw in stateless firewalls?

I am but a lowly (software) developer dabbling with setting up a network in AWS and am having trouble understanding the fundamentals of stateless firewalls, or Network ACLs as they're also referred to ...
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2 votes
1 answer
64 views

Which ranges of IPv6 and IPv4 do requests to the local network and the host?

I'm looking for the range of IP address that is bound to the local network or the host itself. So far for IPv4 I found: 10.0.0.0 - 10.255.255.255 172.16.0.0 - 172.31.255.255 192.168.0.0 - 192.168.255....
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1 vote
1 answer
24 views

Does a Transparent Firewall need a Default gateway if directly connected to a layer 3 device that is actively performing routing?

Good folks of the Network Engineering stack! I have a question that I assume most people could answer in their sleep. To better illustrate my question, I've provided a sketch of my network below. In ...
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  • 13
0 votes
1 answer
30 views

Gateway with multiple VLAN IPs on one NIC [closed]

I would like to separate several hosts from the local network and put them behind a firewall. I would like to use VLANs to "physically" separate them instead of using just different subnets. ...
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1 vote
0 answers
29 views

Pros and cons of directly interconnecting routers and firewalls vs via switch in an enterprise-network? [closed]

In a medium-sized enterprise network, let's say you have a pair of datacenter switches, a pair of distribution switches, a pair of internal core routers, a pair of firewalls, and a pair of edge ...
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3 votes
1 answer
99 views

Juniper SRX 340 route lookup failed

I've a strange issue on my Juniper; I've a policy to allow all traffic to a specific address behind it and, in effect, the policy works correctly. All the traffic I send reach the destination, except ...
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  • 359
0 votes
0 answers
89 views

Active Peer [my FTD IP] already exists

I have configured the Cisco FTD and FMC, now I am trying to add the FTD Device to FMC but the system shows me such an error. Active Peer [my FTD IP] already exists and the the FTD Device doesn't ...
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  • 1
1 vote
1 answer
115 views

Turning Off SPC card on Juniper SRX5800 series Firewall

We are running SRX5800 in a cluster. Each Node has FPCs as well as SPCs installed. Due to some maintenance downtime , we were required to power off FPCs as well as SPCs on a backup node , not in a ...
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  • 1,058
1 vote
0 answers
112 views

SOLVED: Check Point firewall log format through syslog [closed]

I receive logs from a series of Check Point firewalls that I don't manage and they are very thorough, containing every possible information about the communication. They're also formatted like field:&...
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  • 183
-1 votes
1 answer
43 views

Holding session option in Fortiweb

I have Frotiweb installed as my WAF and it is connected to FrotiSandbox for behavioral detection. In the WAF' File Security Policy, I have the "Hold Session While Scanning" turned off and &...
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  • 1
1 vote
1 answer
56 views

NAT in ASA (5505) Firewall is not working for VLANs configured in Layer3 Switch?

Toplogy: Tool Used: Cisco Packet Tracer Scenario: NAT for hosts in any of the VLANs of Layer3-Switch not working. Ping requests reaches outside server, but NAT is not working so ISP Router can't ...
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  • 121
0 votes
1 answer
250 views

How to configure NAT in Cisco ASA Firewall for all VLANs connected to layer 3 switch? [closed]

Topology: How to set up NAT in Cisco ASA Firewall (in Packet Tracer), when there are VLANs in the network? In the current approach, NAT is not working to reach the server (8.8.8.8) from any of the ...
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  • 121
0 votes
1 answer
105 views

Configure AAA on a router - Extended ACLs

How do I write a named extended ACL which will allow for traffic between a DNS from a LAN (IP address) to a DNS server at (IP address), ping from a host PC (IP address) to any destination and allow ...
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0 votes
1 answer
38 views

How to force routing to https website without the IP

I am attempting to limit a group of Chromebooks to access one particular site for student testing. The issue is that the website is secure but the ssl cert is attached to the url not the ip. The ip of ...
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2 votes
1 answer
53 views

Which command is used in Cisco ASA Firewall to display the whole packet flow?

Which command is used in Cisco ASA Firewall to display the whole packet flow on the firewall? This same command allows you to see if traffic is allowed, NATed, or going through a VPN tunnel?
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0 votes
1 answer
352 views

EdgeRouter X select one out of two WANs according to target IP range

I am using IPSET to define the interested IP range. I want to direct packets to one out of two WAN connections according to an IP range. Here are my conditions. A specific IP range. It is defined by ...
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1 vote
1 answer
46 views

Does UDP can be exposed to stateful analysis?

From protocol theory we know that TCP is stateful protocol. Different stateful packet filters do filtration based on connection state. I.e. it can distinguish responses and replies. It's obviously for ...
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  • 207
0 votes
0 answers
22 views

panic:integer divide fault Message Observed on SRX 5800 Routine Engine

We are running 2 x Juniper SRX 5800 Firewalls in a cluster environment. Node 0 got rebooted and Node 1 took over the master role. Node 0 came back online after reboot. The reasons for Node 0 to reboot ...
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  • 1,058
2 votes
0 answers
339 views

Communication between subnets on Sonicwall firewall

I have a Sonicwall TZ-350. X0 is the default LAN with IP 192.168.10.1, and X1 is the WAN. I've set up a second local subnet on X2 with IP 192.168.20.1 for a single NAS device (no switch; the device is ...
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  • 21
0 votes
2 answers
100 views

Adding Second Interface with Different Public IP for Same Internet Connection

We have a situation that I'm not sure how to proceed correctly. This location is currently utilizing two different firewalls - a Sophos XG 310 and a Sonicwall NSA 3500. The way this was originally ...
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1 vote
1 answer
168 views

WatchGuard Geo Location for restricting access to VPN and "Access Portal"

Problem We want to use WatchGuard's Geo Location to restrict access to our "Access Portal" and "Mobile VPN" connections, but see no options and the corresponding "Firewall ...
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  • 121
2 votes
2 answers
174 views

Where should I locate F5 Load Balancer in Network Segmentation?

I segmented my network and locate some important servers behind of firewall. So, I restricted traffic LAN (no segmentation between LAN clients, LAN servers) to/from important servers. These servers ...
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  • 121
1 vote
2 answers
100 views

Bridge mode or straight replacement?

Let's assume the ISP is malicious. They have remote access to their own gateway/router. No way to remove that remote access. But ISP allows using a different gateway/router. Security-wise, what is ...
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  • 175
1 vote
1 answer
637 views

How to find invalid sessions on Juniper SRX 5800 series Firewall

In Juniper SRX 5800 series Firewall , when we run the command 'show security flow session summary node 0' , we see that it shows large numbers of sessions as invalidated. But we don't know ...
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  • 1,058
0 votes
0 answers
51 views

Packet loss at irregular intervals

We have had significant packet loss issues since switching from Sophos UTM SG 310 to the Barracuda Cloud Gen F380 firewall. This has a big impact on live applications like telephony. It is noticeable ...
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0 votes
1 answer
31 views

Unable to Communicate from server to other servers after migrating from existing firewall to new firewall

In our existing environment we had migrated old firewall with new firewall after this activity . we had faced connectivity issue . From servers unable to reach other servers . Post clearing ARP table ...
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1 vote
1 answer
23 views

Let me assume two firewall are connected in active -active mode ,how load sharing happen among two

i wants to know when two firewalls are connected in active -active mode for example A1 and A2 are connected in active -active . if session is initiated from A1 reverse traffic of this session will ...
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0 votes
1 answer
37 views

What is the difference between these two different network security devices?

I have a choice between these two network security appliances, however the only difference I can see is the year and I don't know what that year means. SONICWALL TZ300 WIRELESS-AC SECURE UPGRADE PLUS ...
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1 vote
1 answer
68 views

Is it possible to configure DHCP on a router or UTM firewall for the multiple VLANs on L3 Switch?

I'm working on expanding our office network to accommodate more users/devices. Currently we have the DHCP configured on a UTM firewall(cyberoam ing50) device(cum router) providing IP addresses for ...
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1 vote
2 answers
392 views

Is TLS/SSL inspection throughput important while sizing a Firewall?

Our firm is planning on purchasing a Firewall solution, but are confused with the sizing requirement. We currently have 5 wired internet connections which make a total throughput of 500 Mbps (each ...
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2 votes
0 answers
72 views

Looking for sanitized Palo Alto FW Config

This may sound a bit unusual, but I'm looking for someone who can answer with a sanitized Palo Alto FW text configuration with the following features used: address-groups & service-groups global-...
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0 votes
0 answers
85 views

PaloAlto Application ID Signatures, 7-byte Regex Workaround

I'm in the process of creating some custom Application ID signatures, to give control over some in-house applications. In a nutshell, I've created signatures to match HTTP traffic using the http-req-...
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1 vote
0 answers
277 views

Cisco ASA 5585-x Failover Virtual MAC address

I have configured Cisco ASA 5585-x with Active/Standby mode, cisco best practice saying you should use Virtual MAC address on interface to avoid traffic disruption when you do failover. now question ...
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  • 4,237
0 votes
2 answers
40 views

How to find the client's application port during communication [closed]

After reading firewall rules about inbound and outbount I have some questions and the most sources focus on the server's ports. What happens to the client side when is trying to make a connection to ...
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2 votes
0 answers
343 views

How to redistribute BGP routes learned from AWS in one VR into another BGP running in another VR in Palo Alto firewall?

I have about 1000+ prefixes I am learning from AWS on Palo Alto through a BGP. This is on the secondary VR. Main VR is where my core routing is situated along with another BGP instance pointing to ...
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2 votes
3 answers
898 views

What is the difference between an ASA firewall and UTM firewall?

How do ASA firewalls and UTM perimeter firewalls differ?
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  • 157
0 votes
4 answers
115 views

How common it is to see unknown IPs in logs?

I have a server that streams video to YouTube/Twitch. I see [UFW BLOCK] entries in logs. One IP is 220.133.236.166, the other is 194.26.25.8. Is it a common thing that a server is connecting to my ...
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0 votes
1 answer
43 views

answer packages rejected between mangle/prerouting and nat/prerouting

I am currently configuring a ubiquity edgerouter for our network. We have one uplink port (eth2) and two internal ports (eth0; with vlan 1) and eth3 (with vlans 2,3 and 4). uplink and vlan 1 have ...
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0 votes
1 answer
441 views

Cisco NAT - Overload PAT and Static nat from one inside to two outside interfaces

i have following setup Cisco ISR4k Router with one inside LAN interface and two outside Interfaces. ---- WAN1 (NAT outside) LAN (NAT inside) -- ISR4k | ...
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0 votes
2 answers
50 views

Understanding IPV4 address range [duplicate]

I do have basic understanding of IP Address which is unique address for each System either in an organization or over the internet. But i want to understand what is IP address range Lets Say we have ...
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0 votes
0 answers
102 views

Cisco CML 2.0 strange ASA trunking issue

I am seeing very strange issue and now i am losing my mind so thought ask you folk. I have following two components connected point to point on Cisco CML 2.0 [nxos-9000v]--------------------[ASAv] ...
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  • 4,237
1 vote
3 answers
2k views

Cisco SG-350 Switch and Fortigate Firewall Configuration

I'm not what you would call a Network Engineer, but right now i have a (somewhat) complex network problem that i have to solve. I must configure a SG-35028p cisco switch and a fortigate 60f firewall ...
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0 votes
0 answers
27 views

How much additional processing time is needed for a combination DMZ configuration?

Please consider the DMZ configuration shown below. (Image source: Testing Web Security: Assessing the Security of Web Sites and Applications by Steven Splaine) And then let us consider the following (...
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  • 101
0 votes
1 answer
29 views

Public IP address does not work in internal network [closed]

I have configured port forwarding to my system from the router configuration menu, when I try to access the public IP address in the internal network it does not respond but it is accessible outside ...
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  • 101
0 votes
1 answer
4k views

How to forward port 80 and 443 on pfSense to a (internal) nginx webserver?

Yesterday we did a "big bang" firewall switch in our company. Our new firewall is a pfSense server. Lets say our external ip is 84.1.1.1, pfSense is 192.168.1.1 and our web server ip is 192.168.1.2. ...
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