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48
votes
15answers
7k views

Are IP addresses “trivial to forge”?

I was reading through some of the notes on Google's new public DNS service: Performance Benefits Security Benefits I noticed under the security section this paragraph: Until a standard ...
13
votes
4answers
12k views

Can the IP address for an HTTP request be spoofed?

On a website I am building, I plan to log the IP addresses of submissions, just in case it's necessary. I don't mind proxies, but outright spoofing your IP address would defeat the purpose. To ...
7
votes
1answer
2k views

How to prevent IP spoofing using MAC and ebtables?

I am trying to create IP-MAC pairing rules in ebtables. There are few tutorials and related questions [1] available but I have kind of specific setting. ENVIRONMENT: I have many physical hosts. Each ...
6
votes
5answers
535 views

Any way I can correct DNS spoofing against our domain

This morning I found out that our domain and subdomains have been poisoned on the 4.2.2 and 4.2.2.1 DNS servers along with others I think, though I have not confirmed others yet. Using OpenDNS ...
6
votes
3answers
4k views

How to prevent ip spoofing within iptables?

My Apache web-server on Linux is being flooded by massive requests for a non-existent file. The immediate impact is the rapid growth of the access & error log. I already took care of this by not ...
5
votes
4answers
643 views

MAC address spoofing - why doesn't this work?

So I'm in a new job, and they're pretty draconian about their network, hardware, and OS security. :-( I'm a web developer, but am forced to use IE7 for development simply because they don't want ...
3
votes
3answers
234 views

How to Limit the Damage of Domain Spoofing

My e-mail account, for my privately run business which I'll call "VeryCoolCompany", is starting to receive bounce-backs for users who don't exist, like these: alan12ab1@verycoolcompany.com ...
3
votes
1answer
397 views

How did this email bypass my SPF settings?

I received a phishing email this morning that appeared to come from one of my addresses to itself. Looking at the headers, I found something interesting. DomainKey-Status: no signature ...
3
votes
6answers
2k views

How reliable are IP address-based firewall restrictions?

On some of my production systems that need to be accessible outside of the LAN I will sometimes add a firewall restriction at the edge to only permit traffic on, say, RDP from a specific origin IP ...
2
votes
2answers
97 views

If I use iptables to allow TCP connections only from a specific IP, can it be faked?

An iptables rule on my database server is: -A INPUT -p tcp --dport 6432 -s 10.115.0.150 -j ACCEPT I have other rules (loopback, etc.), but I'm wondering if that specific rule can be "hacked". Can ...
2
votes
1answer
57 views

Does postfix reject spoofed senders?

Is there a reliable way to reject incoming mails with a spoofed e-mail address? What kind of checks does postfix run normally on incoming mails? does postfix check the reverse dns by default? does ...
2
votes
3answers
2k views

Stop spoof emails in Google Apps

Desperately need some help here. I've been using Google Apps for my domain (2qubed.co.uk) for over 2 years now with no problems at all until recently. For the past few months I have been getting lots ...
2
votes
2answers
246 views

Can IP spoofed traffic get above the transport layer?

I'd like to know whether you could get packets with a spoofed IP address above the transport layer. My thoughts are: TCP: No, as acknowledgements would never get to the original sender if their IP ...
2
votes
1answer
607 views

Prevent mail server (sendmail) used to backscatter

Hi I recently got an email from Amazon, saying that my EC2 instance is sending spam. So what they say is my mail server is receiving email for a non-existing user and therefore bounces the email back ...
2
votes
2answers
2k views

Reject obviously spoofed messages in Exchange 2007 SP2

I have an Exchange 2007 SP2 server which happily accepts SMTP messages whose sender is SomeRandomString@mydomain.com and the recipient is SomeRealUser@mydomain.com; this leads to all sort of spoofing ...
1
vote
3answers
950 views

How to avoid DNS spoofing for DNS lookup

I am trying to find a way to obtain the real ip addresse(s) for a domain name. I'm working on a router doing traffic shaping with the use of iptables and tc. I then need to setup iptables rules for ...
1
vote
2answers
137 views

Spoof database connection to be local instead of remote

I am trying to connect one of our clients "as is" programs to a remote database instead of a local one, they think that they have coded it to work that way, but for some reason the program crashes ...
1
vote
2answers
60 views

Wrong DNS answer with CNAME and A Record at the same time

We had a customer which has set a CNAME Record for his domain. Somehow he managed it to set an A Record too, which should be not possible and is forbidden by DNS. But the result was: $ dig ...
1
vote
1answer
324 views

DDoS false IP attack [duplicate]

Possible Duplicate: DDoS attack, how to stop? I'm getting 10MB attacks, IP spoofing, which is used fake IPs, causing high CPU usage of the machine, and falls all. What should I do to ...
1
vote
1answer
735 views

Using arpwatch to backtrack proxy access ip to eap-tls certificate

In my network I am using eap-tls authentication (machine certificates) for clients. Those clients are using a squid proxy to access the internet. The proxy is logging the request to the access.log. ...
1
vote
2answers
192 views

MAC spoofing - keeping the connection alive

Is it possible to keep a connection alive, while spoofing/changing the MAC address of your own network adapter (especially wlan adapter), without needing to re-authenticate against 802.1X ...
1
vote
1answer
157 views

Preventing Email Spoofing

I use Google Apps with my domain. Recently, we have begun to receive spam that gets past Google's spam filters. They are from our own email addresses. I am wondering how to prevent this kind of ...
1
vote
1answer
191 views

Practical way to implement prevention of IP Spoofing

I am an undergraduate Computer Science student and was hoping to gain some knowledge of ways to help prevent IP spoofing but all the resources I have tried out elaborate this concept in a theoretical ...
1
vote
2answers
2k views

ISP login, MAC spoofing, WiFi and multiple devices

I have a Tikona Digital Broadband (WiMax based) Internet Connection which allows limited number of devices to be connected at a time and also requires that the users login with username and password ...
1
vote
1answer
928 views

When a client sends a RST packet, will the server close the connection ?

What I'm trying to do is block RST attacks with IPTables. When I do a search for it, I'm seeing rules where packets with the RST flag set is being rate limited. I'm questioning it a little bit. I ...
1
vote
1answer
736 views

Linux-KVM / iptables: prevent guest spoofing by matching ip+mac address on bridge?

I have my KVM guests on a standard br0 bridge setup: auto br0 iface br0 inet static address 192.168.1.117 netmask 255.255.255.0 network 192.168.1.1 broadcast 192.168.1.225 gateway ...
1
vote
1answer
110 views

Exchange 2010 email spoofing prevention

Masters, Unfortunately we got some spam mail which seems to be coming from our own domain. I found some article which all says to remove Anonymous login from internet receive connector ...
1
vote
0answers
106 views

Woes with named/bind and forwarding zones

I'm sadly restricted to a very old version of bind (9.4.2) This is the think. If I setup bind with a named.conf and only forwarding it works perfect. acl clients { any ; }; options { ...
1
vote
1answer
104 views

Bingbot spoof localhost ip

So here is a fun one. I'm getting bingbot requests at a certain time everyday that kill the server. Here is the request: 127.0.0.1 - - [14/Sep/2013:08:18:49 -0500] "GET / HTTP/1.1" 200 82810 "-" ...
1
vote
1answer
244 views

“From:” e-mail header spoofing - how to verify such mail?

I'm facing a problem of verifying a "From:" message field in e-mail messages, in terms of e-mail spoofing. I am currently using SPF and DKIM to verify the origin and integrity of messages, but as far ...
1
vote
1answer
179 views

Finding spoofed IP address on network

I have a few IP spoof dropped messages coming out of my Sonicwall firewall, we'll call them Source A and Source B. Both of these sources have the same mac address indicating they're coming from the ...
0
votes
3answers
815 views

Exchange and SPF Records

I've created an SPF record on 123-Reg, which is working great. But my question is how Exchange servers know that an SPF record exists when they receive mail from a domain. How does Exchange know it ...
0
votes
3answers
96 views

How to scan for which ports would be open to another location

I'm just assessing the security of my home server in preparation for opening it up to the internet. I've used nmap from a machine on my local network but I have firewall rules allowing access from the ...
0
votes
2answers
2k views

Different Mac address to virtual interface and primary interface

I am developing a system, where I need virtual interface to have different mac address for my primary and virtual interface lets say my mac for eth0 is 00:11:00:11:00:11 and my virtual interface is ...
0
votes
1answer
181 views

iptables: is it possible to spoof NEW packets and make them look like ESTABLISHED packets?

See title for the question. This question relates to a previous question wherein I asked the difference between NEW,ESTABLISHED and RELATED , see it here iptables: difference between NEW, ESTABLISHED ...
0
votes
1answer
160 views

Counter MAC Spoofing with Cisco

I was wondering if someone could help me with the needed cisco commands to configure a switch to only allow certain mac addresses on certain ports. So that one mac adres can only connect to the ...
0
votes
1answer
294 views

Banner Grabbing Spoofing

I run a windows server 2008 standard R2. Is there a way to spoof the server banner ? So instead of Microsoft-IIS/7.5 it could be anything.
0
votes
2answers
289 views

My exchange 2003 mail server is blocked by RBL lists. Someone is sending spam from inform@mydomain.com

All outgoing email to external recipients from my Exchange 2003 server is getting blocked by RBL lists. I'm new to administrating Exchange and i checked the Message Tracking Center under System ...
0
votes
2answers
117 views

Protecting my Bind dns server from slow kaminsky-style cache poisoning attacks

Dan Kaminsky described how DNS servers could be poisoned with spoofed DNS responses [1]. As I understand it, the problem was that Kaminsky found a way to account for most other sources of randomness ...
0
votes
1answer
36 views

Should I move servers and change email address after email spoofing? [duplicate]

I'm hoping the community can help me shed some light on a recent email spoof. Yesterday my client woke up to find hundreds of bounced failure notices. The client did not personally send any of these ...
0
votes
1answer
203 views

Tracking anonymous e-mail threat

A user spoofed/sent an email from http://emkei.cz/ with a very serious threat. Is it possible to trace this back or are we SOL? There wasn't much in the email headers other than that it came from ...
0
votes
1answer
200 views

Blocking External Mail Sent w/ Spoofed Email Address

We recently got an email from an outside server that had a spoofed "From:" header that was the email address of one of our users. Is there a way to have sendmail reject emails coming in from an ...
0
votes
2answers
252 views

Hyper-V MAC Spoofing security hole

I have a windows 2008 R2 SP1 standard dedicated server and i installed Hyper-V role on it. I'm serving Hyper-V VPSs on this server and i can't trust virtual nodes. now the broblem is each node can ...
0
votes
1answer
3k views

ISA Server dropping packets as it believes they are spoofed

We have ISA Server 2004 running on Windows Server 2003 SP2. It has 2 NICs - one internal called LAN on 192.168.16.2, with a subnet of 255.255.255.0, and one external called WAN on 93.x.x.2. The ...
0
votes
4answers
403 views

I need to somehow change my ip address

i`m in a lan using iptables/masquerade. what i want to do, is to login in a web application.i write my user and passwd and click login and everything is fine, but if i try to modify something in that ...
0
votes
0answers
14 views

SPF Record — fighting spoofing email [duplicate]

We are getting email's from email addresses that are from old employees and the addresses have been deleted. This is spoofing, right? Example getting emails from Doe1@domain.com but Doe1 email has ...
0
votes
1answer
23 views

how to discourage email spoofing

One of my production server emails look like to be spoofed from another network. The team (group or individual or professional company) is sending mass mails out to their list of users, using our ...
0
votes
1answer
61 views

DNS request anomaly

Experts, i have some problem in DNS servers configuration, network diagram is shown in figure: The problem is manifesting as follows: There're 2 DNS servers servicing both internal and external ...
0
votes
2answers
89 views

How to spoof an IP for application that needs this particular IP?

In general, such a problem, there is a system RHEL 6.4 Server with a pair of network interfaces combined into one by bonding. This system IP address: 10.7.7.1. Next on the system running an ...
0
votes
2answers
109 views

Spoofing NS records for pre-transfer DNS testing

I'm about to transfer a domain from one registrar and DNS provider to another, and I want to test the new DNS host before starting the transfer. The new host provides plain DNS service beforehand, so ...