Ethical Hacking Learn to find vulnerabilities before the bad guys do! Gain real world hands on hacking experience in our state of the art hacking lab. Course designed and taught by expert instructors with years of penetration testing experience. 12 student maximum in every class. Certification attempt included in every package. | Computer Forensics Training at InfoSec Institute Gain the in-demand skills of a certified computer examiner, learn to recover trace data left behind by fraud, theft, and cybercrime perpetrators. Discover the source of computer crime and abuse at your organization so that it never happens again. All of our class sizes are guaranteed to be 12 students or less to facilitate one-on-one interaction with one of our expert instructors. |

| Subject: | RE: What could this icmp mean? |
|---|---|
| Date: | Thu, 24 Feb 2005 22:51:58 -0000 |
These are ICMP redirect packets. Your default route is not the best to the desired network so the router is telling the client to use a different router. Its to reduce the traffic on the network. HTH -----Original Message----- From: Tomas [mailto:s.tomas@gmail.com] Sent: 22 February 2005 13:11 To: security-basics@securityfocus.com Subject: What could this icmp mean? Hello list, We have networks (10.30.0.0/24 and 10.30.1.0/24) connected trough VPN and one internet line. The gateways for VPN are 10.30.0.1 from one side and 10.30.1.1 from the other, and 10.30.1.254 for internet (for both networks). I've launched tcpdump today on my internet firewall's internal interface (10.30.1.254) and I found this: 10.30.1.254 > 10.30.1.16: icmp: redirect 10.30.0.4 to host 10.30.1.1 for 10.30.1.16.445 > 10.30.0.4.1959: [|tcp] (DF) (ttl 127, id 7691, bad cksum c76d! differs by 100) (ttl 255, id 23807) I'm a bit confused, what could this icmp mean? First of all, I'm sure that neither of these hosts (10.30.1.254, 10.30.1.16, 10.30.0.4) are sending any icmp requests (I'm not sure about 10.30.1.1; it's not in my control). And the second of all, why the checksum is bad?
| <Prev in Thread] | Current Thread | [Next in Thread> |
|---|---|---|
| ||
| Previous by Date: | RE: Help me, Andrew Shore |
|---|---|
| Next by Date: | RE: encrypted data honeypots and IDS, dissolved |
| Previous by Thread: | RE: What could this icmp mean?, Pablo Moore |
| Next by Thread: | Comparing linux distros., Lars Georg Paulsen |
| Indexes: | [Date] [Thread] [Top] [All Lists] |